By Patrick Appel
David Wasserman, house editor of the Cook Political Report, on the congressional races:

If we take a look at sort of the localized effects that the presidential race could have, there are places in a lot of districts where Democrats are going to have to perform better than Barack Obama if they want to win, including a lot of freshman Democrats. I think a challenge for them is really going to be walking that tightrope and negotiating their support for the Democratic nominee with the needs of their own district and the desires of their constituents. In some other places, the likelihood of a Barack Obama wave really puts Republican incumbents in danger. As we get closer to the election, we can expect the races in Illinois 10, Mark Kirk, Connecticut 4, Chris Shays, and some other districts, to really more closely track the standing of the presidential election in those districts. I think those races are likely to tighten, and those Republican incumbents will need to outperform John McCain by say 5 points in order to survive, which is something that is not impossible for them to do, but it's still going to require a serious effort.

He predicts the Democrats will pick up around 15 house seats in the fall. The rest of his discussion with Stu Rothenberg, Tim Sahd, and Tom Schaller is here.

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