Redistricting and Congressional Control: A First Look

October 25, 2012

In America’s deeply divided political climate, even small changes to district boundaries can determine which party controls Congress. The outcome of redistricting can make the difference between which policies are adopted and which ones are ignored — not just in 2013, but for the next decade. This preliminary analysis focuses on who drew the lines following the 2010 Census — legislatures, commissions, or courts — and how that process could affect electoral competitiveness and the partisan balance of power in Congress in the upcoming election. Many election contests are decided not on Election Day, but months and years before, when states redraw their districts. 

 

 

Download the Report (PDF)

Read the Executive Summary

See the Interactive Map

Overview: Before and After Redistricting

View the Report


Executive Summary

Following the 2010 Census, states redrew Congressional districts across the country. In America’s deeply divided political climate, even small changes to district boundaries can determine which party controls Congress. The outcome of redistricting can make the difference between which policies are adopted and which ones are ignored — not just in 2013, but for the next decade. But redistricting is not just consequential for partisan control. It also affects how communities are represented and determines whether legislators are responsive to the citizens they represent.

What has happened in this redistricting cycle? What will be the likely consequences? Of course, it is too early to say for sure — the votes have not been counted. But it is not too early to make some preliminary assessments. This study — a prologue to a more extensive analysis forthcoming in the spring — features our initial analysis of the 2010 congressional redistricting cycle. It focuses on the likely impact of redistricting on the partisan balance of power in Congress.
Based on our preliminary analysis, it is clear that:

  • Republicans were the clear winners of the 2010 redistricting cycle. Compared to the current partisan makeup of Congress, the net effect of redistricting was roughly a “wash.” However, before redistricting, Republicans were not in position to maintain long-term control of several seats they won in the 2010 election. During redistricting, Republican-controlled legislatures shored up many of their recent gains: The GOP may now be in position to maintain long-term control of about 11 more seats than they would have under the pre-redistricting district lines. As a result, Democrats will find it harder to gain the 25 seats needed to take control of the House in 2012.
  • Democrats and Republicans used redistricting to their political advantage. Where Republicans controlled redistricting, they may now be in position to win nine Congressional seats currently represented by Democrats. Democrats countered some of these gains where they controlled the process, but Republicans redrew the lines for four times as many Congressional seats as Democrats.

Many election contests are decided not on Election Day, but months and years before, when states redraw their districts. Both parties use redistricting to tilt the electoral terrain to achieve specific political objectives. This political gamesmanship brings with it important long-term electoral and policy consequences for voters.

Nonetheless, recent reforms in some states have taken redistricting out of partisan hands — or, at the very least, may have reduced the ability of partisans to manipulate the process to their advantage. For example, California’s new redistricting commission dismantled several incumbent-protecting gerrymanders, reducing the number of safe seats in the state by nine. Meanwhile, Florida, where Republican line-drawers were required to comply with the state’s new “Fair Redistricting” criteria, is the only state where Republican state legislators drew new Congressional districts that may have actually increased the opposing party’s political power.

Of course, it is far too early to draw conclusions about what effects these reforms and others have had. This report is the starting point for the Brennan Center’s ongoing assessment of redistricting and its effects on citizen representation. The analysis in this report is limited to the findings from the most recent redistricting cycle based on available data on partisan voting patterns. This report does not address the fairness of district boundaries, nor does it explore whether communities of interest are effectively represented in the new districts. The analysis also does not draw any causal links between who controlled redistricting and the eventual outcomes of the election.

Following the 2012 election, the Brennan Center will examine other aspects of redistricting, including its effect on minority representation and the fairness of the process, among others. That broader assessment will describe in greater detail the lessons learned from the 2010 redistricting cycle.


Interactive Map

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This interactive map shows the Brennan Center’s district competitiveness ratings for all 435 Congressional districts. For each district, the map also includes estimated partisan voting results from the 2008 Presidential election, as well as the 2012 district ratings from The Cook Political Report, The Rothenberg Political Report, and Sabato’s Crystal Ball. Unlike the district ratings developed by these newsletters, the Brennan Center’s district ratings do not take into account election-specific factors such as candidate popularity and campaign spending that could affect a particular election result. Rather, the Brennan Center’s ratings are based only on the partisan voting history in each district. The ratings are explained in detail in Redistricting and Congressional Control: A First Look.    


Overview: Before and After Redistricting

Table 1: Republican and Democratic Seats in Congress, before and after redistricting. The table shows the number of Republican and Democratic seats in Congress based on the current partisan makeup of Congress and based on competitiveness ratings.


Redistricting and Congressional Control: A First Look