A lot of the buzz about Republican prospects for retaking control of the U.S. House is based on fairly abstract factors, such as historical averages and national generic ballot polls. But in reality, of course, elections are individual contests, no matter how “nationalized” the cycle. And four months and change out from the November elections, it’s worth taking a somewhat more concrete look at the House landscape and where Democrats are vulnerable.

For purposes of this analysis, I’ll use the authoritative (if somewhat conservative, in the sense of caution about predicting incumbent losses) Cook Political Report ratings as of June 24 (no link, because it’s subscription-only). According to Cook’s highly astute David Wasserman, there are 66 seats currently held by Democrats that are involved in competitive races. Of those, nearly half (32) are actually rated as “lean D” at the moment. To win control of the House, Republicans need a net gain of 40 seats, and seven of their own seats are in competitive races, including three (DE-AL, HI-1 and LA-2) that most observers consider very likely to flip. So from the get-go, retaking the House will require a very high win rate for Republicans in competitive races, and/or continued improvement in their overall national standing—i.e., races now deemed “Likely D” slipping into the competitive range.

Looking at the 66 vulnerable Democratic seats, 15 are open. That’s a reasonably large number, but only half of the 30 open seats Democrats had in the last Republican “wave” election of 1994 (Republicans had 26 open seats in 2008, greatly helping the Democrats achieve a second straight big winning cycle). Twenty-five seats, however, are represented by freshmen, traditionally the most vulnerable incumbents. Most significantly, 51 of the 66 seats have a pro-Republican Partisan Voter Index (PVI), based on an average of party performance in the last two presidential elections. This indicates that most Republican gains in November will be a “correction” of recent overperformance by Democrats in House races rather than a true GOP “wave.” And it’s a reminder of the simple but often overlooked fact that because all members of the House face re-election every two years, a “landslide” is not defined by gains, but rather by overall performance. A GOP “landslide” in November would involve gains of closer to 100 seats than to the 40 necessary to eke out a small margin of control.

There are not any large regional disparities among the vulnerable Democratic seats: 18 are in the South, 18 in the Northeast, 18 in the Midwest and 12 in the West. Nor is it easy to typecast vulnerable Democrats by ideology: an analysis of the ideology of Democratic incumbents in competitive races published just yesterday by Swing State Project shows they span the intra-party ideological spectrum quite broadly.

Meanwhile, Nate Silver of FiveThirtyEight has just released an update of his Senate race forecast, which now shows a slight improvement in Democratic prospects compared to his last forecast a couple of months ago.  His model now predicts as a matter of probabilities that Democrats should get through November with 55 senators, with the Republicans holding 44 and, perhaps, one true independent (Charlie Crist). Silver gives Republicans a six percent chance of running the table and taking control of the Senate, a figure that improves to 12 percent if they can convince both Joe Lieberman and Charlie Crist (if he wins) to caucus with them.

Poll Watch

In polling news, two new surveys of the Massachusetts gubernatorial race by the University of New Hampshire and Rasmussen both show vulnerable incumbent Democrat Deval Patrick maintaining a seven-point lead over Republican Charlie Baker, with independent Tim Cahill losing steam. A rare poll of the Wyoming governor’s race (again by Rasmussen) shows the importance of term limits: four different Republicans have sizable leads over three different Democrats, while lame duck Democratic Gov. David Freudenthal enjoys an approval/disapproval ratio of 72/25 (a bit better than President Obama’s 30/70).

Yet another Rasmussen poll is the first post-primary survey of the South Carolina governor’s race, and given the positive hype surrounding Nikki Haley after her runoff win, Democrat Vincent Sheheen should be pleased to be trailing only 52-40 (his approval/disapproval ratio is 50/35, while Haley’s is predictably and perhaps temporarily in the stratosphere at 70/26).  And while it’s hardly that significant at this early stage, it’s interesting that a PPP survey of Texas Republicans shows Newt Gingrich leading the 2012 presidential field, with or without Rick Perry listed as an option. Presumed front-runner Mitt Romney is in the middle of the pack.

Ed Kilgore’s PPI Political Memo runs every Tuesday and Friday.

Photo credit: Dbking’s Photosream