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Mail Ballot Security Features: A Primer

Jurisdictions across the country have a range of security features to protect mail ballots from misconduct.

  • Lisa Danetz
Published: October 16, 2020

Because of the Covid-19 pandemic, Americans are using mail ballots in record numbers this year. Fortunately, the use of mail ballots is not a newfangled idea; it was already deeply embedded in the American electoral system before the coronavirus hit.

Mail balloting originated as a mechanism to allow military voters to participate in our elections.footnote1_ithihsoqFTUK1In this report, “mail balloting” refers to any system that uses a “mail ballot” for voting, regardless of the need for a request to use a mail ballot, the pool of eligible voters, or how the mail ballot may be returned. During the Civil War, its adoption allowed 150,000 Union soldiers to vote “absentee” from the battlefield.footnote2_grviB6NYnvuI2Alex Seitz-Wald, “How Do You Know Voting by Mail Works? The U.S. Military’s Done It Since the Civil War.,” NBC News, April 19, 2020, By World War II, all states allowed soldiers to use mail ballots.footnote3_tbM1IotI3CXx3Alex Seitz-Wald, “How Do You Know Voting by Mail Works?” NBC News, April 19, 2020. Today, all overseas voters can request mail ballots on a permanent basis, without having to make additional requests for each election. Military and overseas voters can even cast a backup mail ballot — the federal write-in absentee ballot — if the original ballot does not arrive in time.footnote4_pyJNoamsOKnG4“Federal Write-In Absentee Ballot Instructions and Information,” Federal Voting Assistance Program, last accessed October 8, 2020,; “Federal Write-In Absentee Ballot,” Overseas Vote Foundation, last accessed October 8, 2020,

In the 21st century, mail ballots have become increasingly prominent in American elections. Since the 2010 federal elections, roughly one out of every four ballots cast have been mail ballots, and a growing number of voters have chosen to vote by mail.footnote5_mj8tCfmX6Z4r5U.S. Election Assistance Commission, Election Administration and Voting Survey: 2018 Comprehensive Report, June 2019,; For elections from 2010 through 2016, percent was calculated by adding the percent of absentee ballots and the percent of vote by mail ballots. “More People Voting Early, Using Mail and Absentee Ballots, Percent Voting Absentee, By Mail, or Early, 2004–16,” Chart, U.S. Election Assistance Commission, October 17, 2017, Since 2000, more than 250 million votes have been cast via mailed-out ballots in all 50 states.footnote6_lS3TAj1SohWo6David Roberts, “The Simple Voting Reform that Works Wherever It’s Tried,” Vox, last updated May 24, 2018,

Mail balloting practices vary by state with regard to voter eligibility, ballot return processes, and whether a mail ballot must be requested or is automatically sent to voters. For the 2020 election, nine states and the District of Columbia, will use the practice often called “vote at home,” in which active registered voters are automatically sent mail ballots and can choose from a variety of ballot return methods.footnote7_fvzGPPYrLU6y7“About Us,” National Vote at Home Institute, last accessed August 5, 2020,; The nine states are California, Colorado, Hawaii, Nevada, New Jersey, Oregon, Utah, Vermont, and Washington. In addition, counties in Montana have the option to use a “vote at home” system. “Absentee and Mail Voting Policies in Effect for the 2020 Election,” National Conference of State Legislatures, last updated October 9, 2020,; Quinn Scanlan, “Here’s How State Have Changed the Rules Around Voting amid the Coronavirus Pandemic,” ABC News, September 22, 2020, Twenty-seven states allow “no excuse absentee voting,” enabling any voter to request a mail ballot for the election.footnote8_dH1UIotQWdCj8Alaska, Arizona, Delaware, Florida, Georgia, Idaho, Illinois, Iowa, Kansas, Maine, Maryland, Massachusetts, Michigan, Minnesota, Montana, Nebraska, New Mexico, North Carolina, North Dakota, Ohio, Oklahoma, Pennsylvania, Rhode Island, South Dakota, Virginia, Wisconsin, and Wyoming. “Absentee and Mail Voting Policies in Effect for the 2020 Election,” National Conference of State Legislatures, last updated October 9, 2020.  In addition, 11 states that generally require voters to have specific excuses to cast a mail ballot will allow voters with Covid-related excuses to vote by mail.footnote9_fZgH7RKmaQ2T9Alabama, Arkansas, Connecticut, Kentucky, Mississippi, Missouri, New Hampshire, New York, South Carolina, Tennessee, and West Virginia. “Absentee and Mail Voting Policies in Effect for the 2020 Election,” National Conference of State Legislatures, last updated October 9, 2020; ”COVID-19 Election Information,” Tennessee Secretary of State and Division of Elections, last accessed October 12, 2020,; See also “Absentee By-Mail Ballot Application for the November 3, 2020 Election,” Tennessee Secretary of State, last accessed October 12, 2020, Finally, three states require voters to assert one of several delineated “excuses” in order to receive and cast a mail ballot, and those excuses have not been expanded to take into account the coronavirus pandemic.footnote10_jmnt1WaIIv4Z10Indiana, Louisiana, and Texas. “Absentee and Mail Voting Policies in Effect for the 2020 Election,” National Conference of State Legislatures, last updated October 9, 2020.

End Notes

I. Is It Safe to Trust Mail Balloting Systems?

Some critics, most notably President Trump, have claimed that mail ballot systems are unusually vulnerable to “voter fraud.” But years of mail voting around the country show this is false and that there is little malfeasance.

Low Rates of Malfeasance

Historically, studies show that the level of malfeasance related to mail balloting is infinitesimally small. Numerous analyses show it remains less likely than being struck by lightning.footnote1_lb5yS2TBnr771Wendy Weiser and Harold Ekeh, “The False Narrative of Vote-by-Mail Fraud,” Brennan Center for Justice, April 10, 2020,

Over the last 10 years, there have been multiple large-scale investigations surveying voting- and election-related prosecutions, prosecution referrals, and/or allegations nationwide. All have found only a tiny incidence of suspected misconduct. Most recently, for example, the Washington Post analyzed data from three vote-at-home states and identified only “372 possible cases of double voting or voting on behalf of deceased people,” out of about 14.6 million voters — or 0.0025 percent.footnote2_vTOX3PWXByBd2Elise Viebeck, “Minuscule Number of Potentially Fraudulent Ballots in States with Universal Mail Voting Undercuts Trump Claims about Election Risks,” The Washington Post, June 8, 2020,–11ea-bb20-ebf0921f3bbd_story.html. The conservative Heritage Foundation, which maintains an online database cataloging alleged election fraud cases from the last 20 years, contains 1200 incidents within its database and has identified 204 involving mail ballots, only 143 of which resulted in a criminal conviction.footnote3_w3Tan77zkUsj3Amber McReynolds and Charles Stewart III, “Let’s Put the Vote-by-Mail ‘Fraud’ Myth to Rest,” The Hill, April 28, 2020,; Significantly, the Brennan Center analyzed the Heritage Foundation database and found that even these small numbers are exaggerated. Rudy Mehrbani, “Heritage Fraud Database: An Assessment,” Brennan Center for Justice, September 8, 2017, In the same time period, roughly 250 million mail ballots were cast in the United States.footnote4_wyVrUbNy8eJ34Amber McReynolds and Charles Stewart III, “Let’s Put the Vote-by-Mail ‘Fraud’ Myth to Rest,” The Hill, April 28, 2020. This “translates to about 0.00006 percent of total votes cast” or, viewed another way, “one case per state every six or seven years.”footnote5_zozbzknESeFw5Amber McReynolds and Charles Stewart III, “Let’s Put the Vote-by-Mail ‘Fraud’ Myth to Rest,” The Hill, April 28, 2020.

Similar results come from a 2012 News21 analysis, in which journalists and researchers created a database of every alleged case of election fraud across the country they could find, from 2000 through 2012. In that twelve-year period, when “billions of votes were cast,” they discovered 2068 alleged cases, 491 (or 24 percent) of which were related to mail ballots — a larger incidence than the Heritage Foundation database indicates, but still less than one allegation per state each year.footnote6_ybKbBfrxsqL76Richard L. Hasen, “Trump is Wrong about the Dangers of Absentee Ballots,” The Washington Post, April 9, 2020, In an even more particularized analysis, a superior court assessing the contested 2004 Washington State gubernatorial election ruled 25 ballots (many absentee) invalid, constituting 0.0009 percent of the 2,812,675 ballots cast.footnote7_uMwbHaFCb7eh7Lorraine Minnite, “The Misleading Myth Of Voter Fraud In American Elections,” Scholars Strategy Network, January 27, 2014,  In short, the multiple analyses consistently show that the incidence of mail ballot misconduct is exceptionally low.

Significantly, despite the dramatic increase in mail ballot use over time, fraud rates have remained infinitesimally small. None of the five states that, prior to 2020, have held their elections primarily by mail has had any scandals since making that change.footnote8_kiYb7ZJzySHT8The five states that used a “vote-at-home” system prior to 2020 are Colorado, Hawaii, Oregon, Utah, and Washington. “States with All-Mail Elections,” National Conference of State Legislatures, last updated April 21, 2020,  As the New York Times editorial board noted, “States that use vote-by-mail have encountered essentially zero fraud: Oregon, the pioneer in this area, has sent out more than 100 million mail-in ballots since 2000, and has documented only about a dozen cases of proven fraud.”footnote9_uBhJWK5c1bv89The Editorial Board, “The 2020 Election Won’t Look like Any We’ve Seen Before,” The New York Times, March 21, 2020, Rounded to the fifth decimal point, that’s 0.00001 percent of all votes cast. As the National Vote at Home Coalition notes, “[i]n the 2016 presidential election, more than 33 million voters, roughly 1 in 4, cast their votes via mailed-out ballots. This was one of the most contentious elections in recent American history, and even alleged instances of mailed-out ballot fraud, much less proven examples, were virtually nil.”footnote10_leyCSQOwlMth10“Debunking the Absentee / Vote by Mail Fraud and Abuse Argument,” National Vote at Home Coalition, last accessed October 8, 2020,

Bipartisan Trust in the System

Before the 2020 election campaign season, there was longstanding bipartisan support for mail ballot systems — a fact showing the broad trust in the reliability of mail balloting.footnote11_injSWozP8tjb11Dominique Erney and Wendy Weiser, “Bipartisan Support for Expanded Mail Voting for 2020 Elections,” Brennan Center for Justice, April 15, 2020,  The five states that, prior to 2020, used “vote at home” mailing — Colorado, Hawaii, Oregon, Utah, and Washington — are a mix of purple, blue and red states. Jena Griswold, Colorado’s Democratic secretary of state, has explained, “[V]ote-by-mail for all . . . makes us more secure. Russia can’t hack a piece of paper [and i]t increases accessibility.”footnote12_i6yeEvgt3TdK12Barbara Rodriguez, “Jena Griswold, the 'Dr. Fauci of Vote-by-Mail’? Colorado’s Top Elections Official on the Key to Safe Voting,” Colorado Politics, last updated September 30, 2020,–11ea-bb8b-b707dbd2344c.html. Similarly, Utah director of elections Justin Lee has stated, “Being a very red state, we haven’t seen anything that helps one party over another at all. We’ve heard less concern about voter fraud than about whether every ballot that should get counted does get counted.”footnote13_p6N6tLxAlPle13David Weigel, “The Trailer: The Fear and Politics around Expanding Voting by Mail,” The Washington Post, April 2, 2020, 

Election officials from both parties expressed trust in mail ballots during the 2020 primary elections. In spring 2020, for example, Republican officials in at least three states planned or publicly considered running all-mail elections in light of the pandemic.footnote14_nt3EF48CcAXj14In the spring of 2020 in Ohio, Republican Governor Mike DeWine and Republican Secretary of State Frank LaRose planned and promoted the state’s first all-mail elections. During a similar timeframe, both Iowa’s Republican Secretary of State Paul Pate and New Hampshire’s Republican governor Chris Sununu publicly stated that, due to the coronavirus, they were considering all-mail elections for November 2020. Erin Murphy, “Iowa Election Officials Pushing Vote by Mail for June Primary,” Sioux City Journal, April 5, 2020,–1ff1–5977–980f-8bc5b5c46dc1.html; Michael Wines, “Voting by Mail Could be What States Need. But Can They Pull It Off?” The New York Times, April 11, 2020, Republican officials in Georgia, Idaho, Iowa, Nebraska, South Dakota, and West Virginia proactively mailed absentee ballot request forms to registered voters.footnote15_yc8q4YJcxQ7Z15Amy Gardner and Elise Viebeck, “GOP Pushes Voting by Mail – with Restrictions – While Trump Attacks It as ‘Corrupt,’” The Washington Post, April 13, 2020,—with-restrictions—as-trump-attacks-it-as-corrupt/2020/04/12/526057a4–7bf8–11ea-a130-df573469f094_story.html?utm_campaign=wp_politics&utm_medium=referral&utm_source=rss; Erin Murphy, “Iowa Election Officials Pushing Vote by Mail for June Primary,” Sioux City Journal, April 5, 2020; “Raffensperger Takes Unprecedented Steps to Protect Safety and Voter Integrity in Georgia,” Georgia Secretary of State, last accessed October 8, 2020, Among states that that held a presidential primary after the pandemic’s onset and that normally require an excuse for absentee voting, all except Texas expanded eligibility to allow broader use of absentee ballots — even though in some cases, such as Alabama, Louisiana, and others, this was led by Republican officials and governors.footnote16_iAk6PjVRYhU416Mike Cason, “Merrill Extends COVID-19 Emergency Absentee Voting Rule to General Election,”, July 21, 2020,; Kelly Mena, “Louisiana Voters Can Now Request Absentee Ballots by Citing Coronavirus Concerns,” CNN, May 8, 2020,

Unfortunately, the bipartisan support for mail ballots has frayed in some places under relentless pressure from President Trump, who regularly tweets unsubstantiated claims connecting mail ballot use with “voter fraud.” For example, 3 of the 16 states that require excuses for absentee ballots have refused to expand their availability to voters. Ohio and Texas are limiting the availability of drop boxes and drop-off locations, alternatives to the Postal Service for return of mail ballots. At least seven states that sent absentee ballot request applications to registered voters for the presidential primary are declining to do so for the general election.footnote17_xlgdpO5UJx6K17This includes Alaska, Georgia, Kansas, North Dakota, New Mexico, South Dakota, and West Virginia. Wendy Weiser, Eliza Sweren-Becker, Dominique Erney, and Anne Glatz, “Mail Voting: What Has Changed in 2020,” Brennan Center for Justice, September 17, 2020, Attitudes around mail voting appear to have shifted in recent months, with fewer states proactively encouraging the practice.

End Notes

II. How Do Mail Ballot Systems Protect Against Vulnerabilities?

Any system — whether software, infrastructure, or elections — will have vulnerabilities that it must take into consideration when designing the overall operation. With respect to elections, for example, this played out on a national scale in 2016 with foreign actors exploiting state cybersecurity weaknesses, and that vulnerability remains.footnote1_fZeXezqa8FPq1The Brennan Center highlights several security features and resiliency measures that can help protect against many such threats. Edgardo Cortés et al., Preparing for Cyberattack and Technical Problems During the Pandemic: A Guide for Election Officials, Brennan Center for Justice, June 5, 2020,–06/Resiliency_Final_0.pdf. To address vulnerabilities specific to mail ballots, states incorporate layers of security features embedded into every mail ballot’s journey.

The features identified below constitute a menu of the most common protective measures that states have adopted to guard against malfeasance. Among other things, mail ballot security measures protect against tampering as well as impermissible voting through impersonation and ballot stuffing. Each state’s processes to address these vulnerabilities are slightly different, as processes have developed over time and election officials and legislatures have figured out which of the measures work best in their respective states.

Protections Against Tampering

  • Paper Ballots: All mail ballots are paper and marked by hand, and thus are considered to be the most secure ballot type.footnote2_bfNuoDQv4kls2“Security Features of Voting by Absentee/Mailed Ballots,” in “Voting Outside the Polling Place: Absentee, All-Mail, and Other Voting at Home Options,” National Conference of State Legislatures, last updated September 24, 2020, Because they are hand-marked, any changes to how they have been filled out are more apparent from the face of the ballot.footnote3_eTIZFSkcFzsE3“Security Features of Voting by Absentee/Mailed Ballots,” in “Voting Outside the Polling Place,” National Conference of State Legislatures, last updated September 24, 2020.  Because there is a paper trail to review, voters’ marks can be examined if there is suspicion of tampering, and most states conduct some kind of post-election audit of their paper ballots.footnote4_gPUaNRWehhre4“Security Features of Voting by Absentee/Mailed Ballots,” in “Voting Outside the Polling Place,” National Conference of State Legislatures, last updated September 24, 2020; “Post-Election Audits,” National Conference of State Legislatures, last updated October 25, 2019,
  • Sealed Envelopes: Mail ballots are returned in sealed envelopes. Some states also provide voters with inner secrecy envelopes, which obscure the details of their ballots. Because envelopes must be sealed, attempts to tamper with a ballot after its submission will be apparent from the state of the envelope.footnote5_n7mXtDSVT9Vd5“If the outer envelope is not signed on the signature line located in the upper left hand corner and sealed, the ballot will not be counted.” “Instructions to Voters Voting A Mail-In Absentee Ballot,” Commonwealth of Kentucky, State Board of Elections, last accessed October 8, 2020,; “(1) The team shall verify that…The return envelope is sealed. (2) If the oath is not signed or the return envelope is unsealed, the team shall refer the envelope to the local board.” Md. Code Regs. and,; “Returning Your Absentee Ballot By Mail,” West Virginia Secretary of State, last accessed October 8, 2020, Any rip or break in the envelope seal can be examined for suspicion of tampering.
  • Secure drop-off locations and drop boxes: A common layer of security to ensure that ballots are not stolen or tampered with — at least for voters who can leave their homes — is secure drop-off locations to which no one but designated election staff has access. In places where all or most voters receive ballots by mail, many voters do not use the Postal Service to return completed ballots; rather, they opt to drop their ballots off at secure polling sites that have drop boxes. Provision of secure drop boxes in convenient locations also reduces the risk of voter coercion by allowing individual voters to maintain autonomy in their ability to return their own ballots. Drop boxes are perhaps one of the most important features in a system that relies heavily on mail ballots. According to the Survey of the Performance of American Elections at Harvard University in 2016, 73 percent of voters in Colorado, 59 percent in Oregon, and 65 percent in Washington returned their ballots to some physical location, such as a drop box or local election office.footnote6_fcgvGkesSmTc6Charles Stewart III, “2016 Survey of the Performance of American Elections,” Harvard Dataverse, 2017, Physical security of drop boxes include a lock or tamper-evident seal, secure fastening to an immovable object if at an unstaffed location, placement behind a counter or otherwise safeguarded if in a staffed location, and/or video surveillance if possible.footnote7_fQjkkZEnLxJd7Matt Barreto et al., Protecting Democracy: Implementing Equal and Safe Access to the Ballot Box During a Global Pandemic, UCLA Voting Rights Project, March 23, 2020, 9, 
  • Ballot Handling and Ballot Security: States ensure the integrity and physical security of mail ballots by limiting the opportunity for malfeasance in ballot handling. This is especially important to deter misconduct by political insiders. Video camera surveillance of ballots — either while in storage (in drop boxes or election offices, waiting for tabulation) or during ballot processing and tabulation — play a part in the detection of ballot tampering.footnote8_msavHxRo9zke8“Quick Start Guide: Absentee Voting and Vote By Mail,” U.S. Election Assistance Commission, November 27, 2017,; “Security Features of Voting By Absentee/Mailed Ballots,” in “Voting Outside the Polling Place: Absentee, All-Mail and other Voting at Home Options,” National Conference of State Legislatures, last updated September 24, 2020,  Other important features include requirements for two-person and/or bipartisan teams any time an individual is handling or in the presence of any ballots, whether to retrieve ballots from the post office or drop boxes, to verify signatures, to open mail ballot envelopes, to separate mail ballots from their envelopes, to prepare ballots for scanning, or to participate in the vote counting process.footnote9_hdGtIaY5br7Y9“Security Features of Voting by Absentee/Mailed Ballots,” in “Voting Outside the Polling Place,” National Conference of State Legislatures, last updated September 24, 2020.  NCSL recommends bipartisan teams, while the U.S. Election Assistance Commission (EAC) recommends having two people with ballots at all times, requiring election officials to take a lunch break at the same time while locking down the ballot reception area, installing security where ballots are stored, and storing empty return envelopes and voted ballots in separate tamper-evident sealed containers.footnote10_hEgKefEMW1Vc10“Quick Start Guide: Absentee Voting and Vote by Mail,” U.S. Election Assistance Commission, November 27, 2017. Other procedures include limitations on who can handle ballots and requiring election staff to be on site with vendors at all times.footnote11_ky5aNiReStYE11“Quick Start Guide: Absentee Voting and Vote by Mail,” U.S. Election Assistance Commission, November 27, 2017.
  • Logs/Records: Maintenance of records and review of logs of important mail ballot related information — as well as transparency that such information will be reviewed — deters ballot tampering as well as ballot stuffing. Records are kept of everyone who mailed a ballot, the number of ballots issued, staff involved in ballot reception, the time at which staff handle ballots, the number of returned ballots (that should be balanced at the end of each day), and the names and addresses of those whose ballot has been received.footnote12_ybOKBUJxNbbf12“Quick Start Guide: Absentee Voting and Vote by Mail,” U.S. Election Assistance Commission, November 27, 2017; “Security Features of Voting By Absentee/Mailed Ballots,” in “Voting Outside the Polling Place,” National Conference of State Legislatures, last updated September 24, 2020. By reviewing this data, anomalies — like a larger than expected number of mail ballot requests or a lower than expected return rate — can be detected and investigations initiated to identify wrongdoing.footnote13_tl7xLsds9BbN13It appears that maintenance and review of logs and records led to the detection of the 2018 wrongdoing in North Carolina. Michael Bitzer, ”Three Lessons from North Carolina’s Tainted Election – and What Comes Next,” The Washington Post, February 25, 2019,

Protections Against Impersonation

  • Authentication of request for mail ballot: When mail ballot requests have been received for the 2020 elections, states have used a range of procedures to make sure the requests have been coming from currently registered voters by checking the voter registration database. Thirty-three states compare information submitted by an applicant with the individual’s voter registration record.footnote14_hBQfavpM4jN014California, Nevada, and New Jersey also compare information submitted by an applicant with the individual’s voter registration record. However, because they will practice “vote-at-home” for the 2020 November Election, we have excluded them from this figure. Of those 33, 16 also conduct a signature verification comparing the application signature with that in the voter registration record.footnote15_t923zsRivjEx15Florida, Kentucky, Maine, Maryland, Minnesota, Missouri, Nebraska, New Mexico, New York, North Carolina, Ohio, Oklahoma, Texas, Virginia, West Virginia, and Wyoming “compare an applicant’s information and eligibility against the voter registration record.” Arkansas, Arizona, Connecticut, Delaware, Georgia, Idaho, Iowa, Illinois, Indiana, Kansas, Massachusetts, Michigan, Montana, New Hampshire, Pennsylvania, Rhode Island, and Tennessee “conduct signature verification in addition to checking information and eligibility against the voter registration record.” “Requesting an Absentee Ballot: How Do Election Officials Verify Applications for Absentee Ballots?,” in “Voting Outside the Polling Place,” National Conference of State Legislatures, last updated September 24, 2020. An additional state requires an oath on the mail ballot request.footnote16_a4cwth6fYgdi16Describing procedure in South Carolina. In addition, D.C. generally considers a voter’s signature to be an affirmation; however, D.C. will practice “vote-at-home” for the 2020 election and therefore will not receive absentee ballot applications. “Requesting an Absentee Ballot: How Do Election Officials Verify Applications for Absentee Ballots?,” in “Voting Outside the Polling Places,” National Conference of State Legislatures, last updated September 24, 2020. Five states require voters to provide additional documentation or take additional steps for verification, and two states issue the mail ballot upon application.footnote17_kSffaGRDtceQ17Voters must provide additional documentation or take additional steps for verification in Alabama, Louisiana, Mississippi, South Dakota, and Wisconsin. Alaska and North Dakota issue a mail ballot upon application. “Requesting an Absentee Ballot: How Do Election Officials Verify Applications for Absentee Ballots?,” in “Voting Outside the Polling Place,” National Conference of State Legislatures, last updated September 24, 2020; “VOPP: Table 8: How States Verify Absentee Ballot Applications,” National Conference of State Legislatures, last updated April 29, 2020,; Vermont will practice “vote-at-home” for the 2020 election but, in other elections, reviews the application for completeness before issuing an absentee ballot. Vt. Stat. Ann. Tit. 17, §2533. Depending on the state and other practices, the verified absentee voter may be removed from the pollbook (used to check in voters at the polling place) after a clerk sends the mail ballot packet.footnote18_jyuZ2aC8WUoY18Matt Blaze, “Rapidly Scaling Up Absentee Voting In An Emergency,” March 10, 2020, 5, In other states, voters are not removed from the pollbook, but only one ballot will be recorded and any additional ballots will be automatically canceled (as a result of bar code features).footnote19_eB5sWJzAzWFO19Matt Blaze, “Rapidly Scaling Up Absentee Voting in An Emergency,” March 10, 2020, 5.  
  • Individualized ballot envelopes: Mail ballot packets sent to voters are individualized for each voter and include individualized return envelopes. The ballot envelopes generally include an individualized serial number or bar code as a mechanism to ensure there is only one vote per individual voter. Indeed, most election jurisdictions now use some form of bar code on their ballot envelopes. These bar codes allow election officials to keep track of ballot processing and help voters know whether their ballot has been received. Bar codes also allow states to identify and eliminate duplicate ballots if more than one ballot has been cast in a voter’s name, whether mistakenly or corruptly.
  • Ballot Tracking: Knowing where a mail ballot is during all steps of its round-trip journey — from an election office to a voter and back to an election office for processing and tabulation — limits the opportunity for a ballot to be diverted from where it should be and to whom it should be sent.

There are multiple types of ballot tracking, as well as systems that integrate these underlying tracking devices to provide elections officials and voters with easier access to information about mail ballots. The first mail ballot tracking device is the U.S. Postal Service’s Intelligent Mail Barcode (IMB). Many jurisdictions, including California, Colorado, and Florida, equip their ballot envelopes with intelligent mail bar codes to enable tracking of ballot envelopes through the U.S. mail.footnote20_rZre8k6FlNoU20“Steps to Creating Your Intelligent Mail Barcode,” United States Postal Service, 2018,; See also “Vote-by-Mail Envelope Design for California,” Center for Civic Design and California Secretary of State’s Office, December 15, 2017,; Jenny Blessing et al., “Security Survey and Analysis of Vote-by-Mail Systems,” submitted May 18, 2020, last updated September 5, 2020, 2,; “Florida State Association of Supervisors of Elections Meeting,” United States Postal Service, December 2015, IMBs are primarily used to track mail ballots on their way from elections offices to voters, though some jurisdictions also use them to track return of completed mail ballots.footnote21_qLMLaL7SEkGB21Interview with Jessenia Eliza, Director of Government Initiatives, Democracy Works, June 4, 2020. More often, a different type of postal code, which slightly modifies the original IMB, is used for return of mail ballots from voters to elections offices. The final ballot tracking device — called “internal bar codes” in this report and referenced above in the entry regarding individualized ballot envelopes — is not a postal bar code but rather allows elections officials to track mail ballots as they make their way through the voting process, from issuance to a voter, to receipt by the elections office, to rejection or acceptance, to tabulation and counting.footnote22_gifIi4AMysUp22“Quick Start Guide: Absentee Voting and Vote By Mail,” U.S. Election Assistance Commission, November 27, 2017; “Security Features of Voting By Absentee/Mailed Ballots” in “Voting Outside the Polling Place,” National Conference of State Legislatures, last updated September 24, 2020. Most jurisdictions across the country use these internal bar codes as part of election administration.  

Two software systems (run by Ballot Scout and BallotTrax), as well as some in-house jurisdiction-specific systems, provide comprehensive tracking services, leveraging the underlying tracking systems described above and providing access to voters. The comprehensive commercial systems track mail ballots from the time they are placed into the mail, to eventual receipt by voters, to return receipt at election offices, until acceptance for counting, even proactively alerting voters of important steps in the process.footnote23_qacEGKM6NmJK23Talib Visram, “’Track Your Ballot like a Package’: How Technology Will Smooth the Way for November’s Mail-In Ballot Surge,” Fast Company, May 7, 2020, Forty-three states plus the District of Columbia allow voters to track their mail ballots, while another four provide mail ballot tracking for a subset of voters.footnote24_tacyc3OG2eaC24Ballot tracking is offered may be offered by counties in Colorado, Illinois, and Wyoming. Texas provides ballot tracking only to overseas and military voters. “Where’s My Ballot?” U.S. Vote Foundation, last accessed October 6, 2020, Using ballot tracking, if a voter says she or he never received a ballot, an election official can better determine whether the ballot was delivered, replace the ballot as appropriate, and ensure the original is flagged as compromised and not counted. The systems can also let a voter know if, upon receipt of the ballot, there are problems or deficiencies that need correction — also an important trigger to determine if the correct person is returning the ballot.

  • Identity Verification: The principal method used to detect and prevent individual fraud is the mail ballot envelope itself, which includes personal identifying information. In most states, that information includes a signature that can be used to compare against the voter rolls. In other states, there may be an affidavit, witness, or notary required.footnote25_jiRphIJ3uSEr25“VOPP: Table 14: How States Verify Voted Absentee Ballots,” National Conference of State Legislatures, April 17, 2020, Laws requiring an affidavit or signature comparison to verify a voter’s identity — rather than a witness signature or a notarized signature on the mail ballot envelope — are preferable because they reduce opportunities for coercion by necessary third parties.footnote26_rz31u7ATkFBQ26A state’s requirement for a witness or notary, the choices of whom may be quite limited during the pandemic, increases the risk of voter coercion by requiring the involvement of an individual other than the voter. Three-quarters of states plus the District of Columbia protect voters in this way.footnote27_oZzmcspK8UMw27“VOPP: Table 14: How States Verify Voted Absentee Ballots,” National Conference of State Legislatures, last updated April 17, 2020. When a mail ballot is returned, the signature or personal identifying information is compared against the information stored on the voter rolls. As Kim Wyman, Washington’s Republican secretary of state, explained, “We actually compare every single signature of every single ballot that comes in and we compare it and make sure that it matches the one on their voter registration record.”footnote28_ts19reFFfwiK28Kristine Frazao, “New Calls Rising to Change the Way Americans Vote in the Midst of a Pandemic,” CBS Austin, April 7, 2020, This is a long-standing and well-established practice to ensure that the ballot received was indeed cast by the correct voter.
  • Tabulator system design: Ballot scanning (also called tabulating) systems, through which mail ballots are processed upon their return, incorporate features that will detect and/or reject counterfeit ballot forms.footnote29_fkNasaUz3jhU29Matt Blaze, “Rapidly Scaling Up Absentee Voting In An Emergency,” March 10, 2020, 7.

Tabulator vendors issue printer specifications for the paper that must be used for ballots in order for the ballot to be scanned and read correctly by the vendor’s tabulator. Qualities like the paper’s weight, brightness, and opacity, as well as the color and type of ink, are specified. For example, mail ballots are typically pre-printed with a combination of infrared absorbing and infrared reflecting inks that must appear in specific places on a ballot.footnote30_wmz0Rdp0tOXv30Matt Blaze, “Rapidly Scaling Up Absentee Voting In An Emergency,” March 10, 2020. Tabulator vendors certify different print shops, which have the printer specifications and can produce ballots correctly, and therefore tabulators only guarantee that ballots produced by those shops will scan correctly. Ballots that do not meet the printer specifications are not guaranteed to scan in the tabulator, and a sufficient number of ballots rejected by the tabulator will raise suspicion. Some tabulator vendors jealously guard printer specifications and therefore only certified print shops have the relevant information to print ballots at all, making ballots even harder to produce fraudulently.

In addition, ballots have “timing” marks, which are hard to reproduce. The specific location of timing marks — down the side of the ballot — allow tabulators to understand how to “read” the ballot. Timing marks are different for each ballot style, and also for each election. The need to reproduce timing marks for a ballot to be counted correctly is another feature that makes fraudulent production of ballots, and the subsequent successful counting of such ballots if cast, difficult.

  • Signature cure process: When a signature is missing from a returned mail ballot envelope and/or the signature on the envelope is not comparable to the signature in the voter registration database, a state’s cure process — contacting the registered voter to fix the problem — is an important process to determine whether the ballot was stolen and fraudulently cast or, more likely, whether the voter’s handwriting was poor because of, for example, a broken arm or a changed signature over time. Eighteen states have a statutory process that seeks a voter’s “cure” of perceived signature problems.footnote31_tV0iHyLrHF2b31This includes Arizona, California, Colorado, Florida, Georgia, Hawaii, Illinois, Iowa, Massachusetts, Minnesota, Montana, Nevada, New Jersey, Ohio, Oregon, Rhode Island, Utah, and Washington. “Processing, Verifying, and Counting Absentee Ballots: What happens if there is a missing signature or a signature discrepancy?,” in “Voting Outside the Polling Place,” National Conference of State Legislatures, last updated September 24, 2020.
  • Provisional Mail Ballots: If a voter requests a mail ballot to be sent to a different address after a mail ballot package is already sent, a provisional ballot is sent to the second address and, by relying on a bar code, counted only when it is clear the first ballot has not been returned. Provisional ballots are also sent when a voter complains that the original mail ballot packet has not been received.

In addition to these measures, regular voter-protective list maintenance (discussed below in the section describing protections against ballot stuffing) also provides protection against impersonation.

Protections Against Ballot Stuffing

  • Regular voter-protective list maintenance, i.e., making sure there are accurate addresses: By conducting a regular program of list maintenance and keeping up-to-date address information, states can be confident that mail ballots (or mail ballot requests) are sent to registered voters at their correct addresses.footnote32_kBsYABI7Qrrj32“Security Features of Voting By Absentee/Mailed Ballots,” in “Voting Outside the Polling Place,” National Conference of State Legislatures, last updated September 24, 2020. This is particularly important in states that send ballots to all registered voters. When ballots are sent to addresses that have not been updated regularly, they may get delivered to locations where voters no longer live, creating a potential opening for a dishonest individual to attempt to submit a ballot that belongs to someone else. (Identity verification, as described above, is designed to prevent any fraudulently submitted ballots from being counted.)

Effective list maintenance is an important security measure, yet states must be careful to include adequate safeguards to ensure eligible voters remain registered. Over-aggressive list maintenance risks disenfranchising properly registered voters who should be able to cast a ballot.footnote33_oiTNqy1WMTos33Kevin Morris, Myrna Pérez, Jonathan Brater, and Christopher Deluzio, “Purges: A Growing Threat to the Right to Vote,” Brennan Center for Justice, July 20, 2018, Many states conduct list maintenance through membership in ERIC, the Electronic Registration Information Center, which assists members by comparing databases and alerting them of inaccurate and out-of-date voter registration records.footnote34_l1PH21WvGj1q34See Electronic Registration Information Center website, last accessed October 14, 2020, Currently, 30 states plus the District of Columbia are ERIC members. Note, however, that ERIC members who are not subject to the National Voter Registration Act — like Minnesota and Wisconsin — have different rules governing removal from the voter registration list than the remaining members.

Policies that make it convenient for voters themselves to update their addresses also help keep voter registration lists up to date. For example, both Section 5 of the National Voter Registration Act and automatic voter registration require automatic update of voter registration addresses (unless the voter specifies otherwise) when voters update their driver’s license addresses. Moreover, sending mail ballots itself aids in the effort to ensure accurate voter registration lists. According to NCSL, “The act of sending out absentee/mailed ballots also allows election officials to ensure they have up-to-date addresses for voters, and states that send out more absentee/mailed ballots have seen an added benefit [that] . . . voter address information is kept up to date.”footnote35_vq3bm0OjPGgq35“Security Features of Voting By Absentee/Mailed Ballots,” in “Voting Outside the Polling Place,” National Conference of State Legislatures, last updated September 24, 2020.

While regular list maintenance limits mis-delivery of mail ballots, failure to use best practices will not create election-related risks in the (overwhelming) majority of states that require voters to request their mail ballots.

  • Ballot tabulation practices: The EAC recommends that states establish written procedures for manual duplication of voted ballots to make sure each vote is counted only once and that states, post-ballot tabulation, balance the number of mail ballot return envelopes with the tabulation (minus any exceptions).footnote36_p4Q6XkZOQFyA36“Quick Start Guide: Absentee Voting and Vote by Mail,” U.S. Election Assistance Commission, November 27, 2017. In addition, transparency in counting ballots ensures no malfeasance by insiders and gives confidence in election outcomes.footnote37_xJAZSoiCbJHC37Interview with Brian Corley, Pasco County Florida Supervisor of Elections. May 7, 2020.
  • Postelection audits: Postelection audits enable election officials to identify irregularities or misconduct in the counting of votes. Such audits typically use statistical techniques to review a sample of ballots cast in an election to ensure that votes were recorded and tallied accurately. Since audits of the vote count can only be meaningfully carried out when there is a voter-verified paper record of each vote, mail ballots (which are paper-based) are conducive to effective audits. Such audits also help ensure the integrity of ballot scanning (tabulating) software.footnote38_gPIkhyY3MfI438Matt Blaze, “Rapidly Scaling Up Absentee Voting In An Emergency,” March 10, 2020, 7, Postelection audits are already widely used in states and risk-limiting audits, one particular type of post-election audit, are a best security practice for all elections.footnote39_s9U2mWjm9qWT39“Post-Election Audits,” National Conference of State Legislatures, last updated October 25, 2019; Christopher Deluzio, “A Smart and Effective Way to Safeguard Elections,” Brennan Center for Justice, July 25, 2018,

In addition to these measures, authentication of requests for mail ballots, individualized ballot envelopes, tabulator system design, and maintenance of logs and records provide protection against ballot stuffing.

General Protection Against All Forms of Malfeasance

  • Harsh penalties: Anyone who commits voter fraud of any kind using a mail ballot risks severe criminal and civil penalties: up to five years in prison and $10,000 in fines for each act of fraud under federal law, in addition to any state penalties.footnote40_dnyfEKw90NTu40Citing 52 U.S.C. § 10307 and 52 U.S.C. § 20511. Justin Levitt, “The Truth About Voter Fraud,” Brennan Center for Justice, November 9, 2007, 7, In Oregon, for example, voting with or signing another person’s ballot, requesting a ballot in another’s name, voting more than once at an election, willfully altering or destroying a cast ballot, and placing a fraudulent ballot among genuine ballots are all Class C felonies punishable by up to five years in prison.footnote41_sAffwIPQfV4P41Identifying violations of Or. Rev. Stat §260.715 as Class C felony. “Election Law Summary,” March 2016, 46, Indeed, in all “vote at home” states, any attempt to commit election fraud with mail ballots is a felony subject to 5 years of prison time.footnote42_z5XT1JJ8xjDI42“’Vote at Home’ What It Is, Best Practices and Lessons Learned,“ National Vote at Home Institute, Spring 2020, 4, These penalties are important security features that provide a strong deterrent to misconduct; it makes no sense for an individual to risk such significant punishment.

End Notes

III. How Do These Security Features Collectively Prevent Mail Balloting Misconduct?

Certain concerns about the mail ballot process have been raised repeatedly in public discussion, both by concerned citizens as well as opportunistic partisans. The question-and-answer below describes how the security features defined above work collectively to minimize misconduct in mail balloting.

Question: I’ve heard that mail ballots are being delivered to people who have moved and have even been left in piles on the floor of apartment building lobbies. I’ve also heard that mail ballots can be stolen from people’s mailboxes. How do states prevent individuals from fraudulently voting a mail ballot meant for someone else?

Answer: As a threshold matter, the postal delivery carrier should not be leaving mail ballots outside of mailboxes. In addition, stealing ballots is a federal crime, punishable by up to five years in prison and $10,000 in fines.

With respect to sending and processing mail ballots, there are many security features beyond criminal penalties that deter and prevent the fraudulent casting of a mail ballot sent to someone else. As a threshold matter, ballots are either sent proactively to addresses already on file for registered voters or to registered voters who have requested a mail ballot (and whose registration status have been verified as part of the application process). Then, several security features protect the return and submission of the mail ballot. For example, the voter must put his or her ballot in an envelope or sleeve that requires the voter to fill in information that only he or she would know. When the ballot is returned to the election office, an identity verification process takes place. Usually, that means there will be a signature comparison. If the ballot is submitted fraudulently, the signatures and/or other personal identifying information written on the envelope or sleeve will not match. Moreover, in states that have a signature cure process, the failed signature match will trigger contact with the correct voter, who will be notified that a mail ballot was submitted in his or her name. The voter can then report the theft of the ballot, and authorities can investigate the matter.

Finally, if a voter contacts an election official to report that he or she has not received his or her mail ballot, the election officials can track the ballot through the individualized internal bar code. The bar code will allow officials to identify and cancel a stolen mail ballot and send a new mail ballot to the correct person. It is only after the identity verification, signature cure, and attendant processes have been completed that a mail ballot proceeds to be counted. If an investigation identifies any fraudulent submission (or attempted fraudulent submission), harsh penalties are imposed.

Question: How can states be sure that individuals who are collecting ballots for delivery do not coerce the voters to vote a certain way, modify their ballots, or throw their ballots into a river?

Answer: There are legitimate reasons, especially during a pandemic, for people to want assistance in delivering their ballots. People may be immunocompromised and somewhat housebound, they may lack transportation, or they may be challenged by any number of obstacles to submitting their mail ballot. Indeed, an individual who is relying on ballot collection assistance has the choice of whether or not to rely on an individual’s assistance, and most will rely only on someone he or she deems trustworthy. Nevertheless, the more options a state can offer for ballot submission — like secure drop boxes in convenient locations, as well as postal delivery — the less likely a voter will need to rely on someone else for assistance. When a voter does rely on someone else to deliver his or her ballot, the voter must seal the ballot in the specifically provided ballot return envelope. The sealing of the ballot inside an envelope is specifically intended to prevent tampering. Many states require the voter to identify in writing his or her designated agent (for return of the ballot) or require the individual who delivers the ballot to sign the outer mail ballot return envelope.footnote1_eYakWdphPErh1For example, California requires the voter to fill out an “authorization section” on the outside of the ballot envelope and New Jersey requires the assister to sign the outer mail ballot return envelope. “Returning a Voted Absentee Ballot: Who Can Collect and Drop Off an Absentee/Mailed Ballot on Behalf of a Voter?,” in “Voting Outside the Polling Place,” National Conference of State Legislatures, last updated September 24, 2020; “Vote by Mail,” California Secretary of State, last accessed October 14, 2020,; Katie Sobko, “All of Your Questions About Voting in the Nov. 3 NJ Election, Answered Here,”, published September 29, 2020, last updated October 8, 2020, If a voter’s ballot has been modified, visual inspection will likely show that the face of the paper ballot has been altered (because, for example, there will be a second mark or it might look like there has been an attempt to remove one mark and add another). Finally, the mail ballot can be tracked to confirm it has been returned. In many states, identification of the person providing a voter with assistance allows investigation of suspicions, and harsh penalties will be imposed if the assister engages in misconduct.

Question: How can we be sure that foreign nations are not creating and voting with counterfeit ballots, as suggested by U.S. Attorney General William Barr?

Answer: As a threshold matter, this answer assumes the posed question is concerned with a foreign nation that desires to create and vote with counterfeit mail ballots for the purpose of impacting the election outcome, rather than for purposes of disinformation, and would therefore need to create and vote significant numbers of fraudulent mail ballots.footnote2_v5S8s0t1lCop2A foreign nation seeking to create and vote fraudulent ballots for purposes of disinformation need only create a handful of mail ballots, specifically designed to be caught and identified, for purposes of media amplification and fearmongering about the mail-in ballot process. To do so, the foreign nation would need to have knowledge of information from many different sources and that is difficult to access, especially for the numbers of voters from whom the foreign nation would need to attempt to steal votes. The larger the number of fraudulent ballots at issue, the more likely the perpetrator of the fraud is to be caught.

In order for a foreign nation to engage in the type of conduct posed by the question, the nation would need to undertake all of the following — a difficult enterprise. In sequential order, the nation first would need access to the names and personal identifying information of voters (including, for example, non-public information like a digital image of a signature and/or a driver’s license number or last four digits of a social security number), and therefore would need to access statewide voter registration databases without detection by state officials. In states where voters request mail ballots, the nation also would need to know which specific voters already made such requests. The nation would need to be assured that voters they chose did not or would not request a mail ballot either before or after the foreign nation did so, thereby alerting the election official that some type of misconduct was occurring — particularly difficult to do in large numbers when so many voters will use a mail ballot in the 2020 general election. The nation would need to redirect the mail ballots, requesting that they be sent to locations other than the voters’ homes and would need many locations for the redirection — if 10,000 mail ballots are all requested to be sent to the same address, that will raise red flags for election officials. The nation would need to know the printer specifications for the tabulator (which are not generally available), the exact ballot style for each such voter, and how to accurately reproduce the timing marks for each such ballot style (all information held by the tabulator and print shop) in order to reproduce the mail ballot for the voters. The foreign nation would need to know, and be able to replicate, both U.S.P.S. IMBs and internal bar codes (information from U.S.P.S. and election officials’ offices). As stated above, the nation must have access to each voter’s signature and be able to accurately forge each signature for a signature comparison. Finally, the nation must be able to submit the mail ballots before the actual voters so that the fraudulent ballots are counted rather than the validly cast mail ballots by the specific voters. Consequently, any foreign nation wishing to engage in the creation and casting of a large number of fraudulent mail ballots would have to access closely held information of state or local election officials, private vendors, the U.S. Postal Service, and individual voters. Every incremental new piece of information necessary for this scheme makes it harder to implement.

Question: I heard President Trump say that mail ballots with his name were found in an election office wastepaper basket. How can we be sure mail ballots are not being disposed of prior to tabulation?

Answer:  In Luzerne County, Pennsylvania, officials discovered nine discarded overseas mail ballots — which look different than regular mail ballots and are sent in envelopes that are not clearly marked as containing ballots. A confused temporary election worker had improperly disposed of the ballots and was fired. The incident was likely the result of insufficient training and is under investigation by authorities.

States adopt a host of ballot handling procedures precisely to prevent and/or identify improper disposal of ballots — and these processes appear to have worked in this instance. For example, two-person and/or bipartisan teams are present any time an individual is handling or in the presence of ballots, and there are limitations on who can handle ballots. Video camera surveillance monitoring unattended ballots allows identification of anyone who improperly destroys or discards ballots. Logs that record important data — including staff involved in ballot reception, the time at which staff handle ballots, and the number of returned ballots — allow the number of ballots counted to be balanced against the number of ballots received on a particular day, and any anomalies to be attributed to particular staff present.

End Notes


Because of the Covid-19 pandemic, states are relying more heavily on mail ballots in 2020. As many states have pivoted to accommodate greater usage of mail ballots, there have been loud but unproven claims about the vulnerability of mail ballots to malfeasance. Experience demonstrates that mail ballot systems are secure — there has been fewer than one instance of mail ballot misconduct per state per year — and there is broad support across the political spectrum for its reliability.

All voting methods — indeed, all systems — have vulnerabilities, and mail ballot systems are no different. Thankfully, there is a menu of security features to protect mail voting — from broad availability of secure drop boxes to ballot tracking to identity verification to ballot security to post-election audits — and features have been adopted by jurisdictions across the country. These features have kept mail ballot related malfeasance rare and should give the nation confidence that the upcoming mail ballot systems will be secure.