What might happen in the 2010 House elections

Nate Silver links to a Congressional Quarterly list of ratings for 2010 congressional races and concludes that, although these listings give a sense of which races are more likely to be competitive, the CQ chart doesn’t really say much about the chance that there will be a “wave” election that would switch partisan control to the Republicans.

The same day, Matthew Yglesias links to a recent Congressional Quarterly report entitled, “2010 House Outlook: Democrats Look Secure” and concludes that, yes, the Democrats look secure to keep their House and Senate majorities.

What should we believe? For the purpose of campaign strategy, you need to look at the races in each district, but to get a sense of what’s going to happen overall, I think the best approach is to look at the national vote. There’s lots of variation, but, overall, swings occur nationally.

Here’s a graph I made after the election, showing the average Democratic share of the two-party vote for the House of Representatives and for president for the past sixty years:


From this picture, it looks possible but unlikely that there will be a 6% swing toward the Republicans (which is what it would take for them to bring their average district vote from 44% to 50%). Historically speaking, a 6% swing is a lot. The biggest shifts in the past few decades appear to be 1946-48, 1956-58, and 1972-74 (in favor of the Democrats) and 1964-66 and 1992-194 (for the Republicans). I don’t know if any of these would quite be enough to swing the House majority. A more likely outcome, if the Republicans indeed improve in next year’s election, is for them to make some gains but still be in the minority.

The other factor helping the Democrats is incumbency, which helps lock in a congressional majority (as it did for the Republicans after 1994) by bumping up the vote shares of the new congressmembers elected in swing districts. In 2008, John Kastellec, Jamie Chandler, and I estimated that the Republicans would need something like 51% of the average district vote to have an even shot of winning a majority of House seats.

P.S. Beyond the particular issue of forecasting the 2010 election, both pundits make interesting points. Nate discusses some factors that could help the Republicans (a continuing economic slump) and, on the other side, the Democratic Party’s advantage in organization and fundraising. Yglesias suggests that, “given the contrast between ironclad discipline on the GOP side and the ‘anything goes’ attitude on the Democratic side, it looks like for a while yet we may be in a California-style dynamic where Republicans can’t win elections but Democrats can’t actually pass a governing agenda.”

3 thoughts on “What might happen in the 2010 House elections

  1. These analyses generally overlook the continuing and significant demographic changes that put the Republicans at a real disadvantage. As the citizen children of the huge Reagan wave of illegal immigration come of age, the Republican inability to attract Hispanic voters puts the party in real danger of irrelevance. The party's self-immolation over the Sotomayer nomination is just the latest evidence of a party trapped by the baser instincts of its base.

  2. Looking at the graph, what stands out to me is that the Congressional vote shares have fluctuated much less than the Presidential vote shares, and second how much the electoral map in 1995-2007 favored the Republicans, it looks like the Democrats won or at least tied the popular vote in most of those elections.

    The bottom line is that the Republicans need a 6% swing, and will get it if the bottom falls out for the Obama administration (e.g. no health care bill, or one that actually winds up removing coverage for people like the Baucaus bill; no withdraw from Iraq; worsening economy). There really isn't much analysis that can be done before that and looking at things district by district at this point is stupid. We don't even have a sense of where the retirements will be or what candidate recruitment will be like.

    My gut feeling is that we will probably get something like the 1930 election, which saw a swing to the non-presidential party but resulted in a virtual tie in Congress, or maybe 1978 or 1990, which on the surface reaffirmed the status quo with some interesting things going on if you looked at the details. But this is just a gut feeling based on historical precedence.

    It seems to be that US politicians have a hard time doing opposition politics. The Democrats were too prone to agree with whatever the White House proposed when they were on the outside, the Republicans have the opposite problem of opposing anything and everything but not being able to really explain why or to offer anything constructive.

  3. Very good post indeed. But you don't take into account the greatly increased polarization since 1994 and the greatly increased tendency of like-minded people to live in communities with like-minded people. I can tell you as a 45 year old gay man, I would not live (or locate my business's facilities for that matter) in an unwelcoming state or area. Thus I live in Henry Waxman's CA district now having moved recently from Carolyn Maloney's NY district.

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