In 2012 election, GOP kept majority through incumbency and structural bias

Partisan bias in U.S. House elections

By Rob Richie, WashPost, Published: November 15

Rob Richie is executive director of FairVote, a nonpartisan organization based in Takoma Park, Maryland.

Barack Obama won a clear victory in the presidential election, and Democrats won 25 of 33 Senate races. But they failed miserably to win the House, falling short by more than 30 seats. How could the same voters deliver such different outcomes?

The answer lies in the way we elect House members. Because of where each party’s voters live, Republicans have an intrinsic advantage under today’s winner-take-all voting rules. Left unreformed, the rules will distort House representation for at least a decade.

Last week, Democrats won the most votes in contested House races. FairVote’s post-election analysis of partisan voting trends suggests an underlying national preference toward Democrats of 52 percent to 48 percent. (If there had been no incumbents and each party had run a candidate in every district, the Democrats would have won 52 percent of the votes.) With a comparable edge in 2010,

Republicans gained 64 seats to take the House. But this year, winning a House majority would have required a much bigger swing toward Democrats, as much as 55 percent of the vote, a historical high.

Incumbency and campaign spending helped Republicans, but their biggest advantage is structural. We elect House members in 435 districts, each with one representative. If ordered by their partisan leanings, 241 districts tilt toward Republicans. Only 194 lean toward Democrats. Of districts where one party’s underlying advantage is at least 8 percentage points, Republicans have the edge in 195 and Democrats in 166.

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