Even a Biden recovery loses Dems the house – drags down key races

[(J. Miles, associate editor of Sabato’s Crystal Ball, the University of Virginia Center for Politics’ authoritative, nonpartisan newsletter on American campaigns and elections.) “How Current Presidential Polling May Impact House Races”, Center For Politics, July 11th 2024, https://centerforpolitics.org/crystalball/how-current-presidential-polling-may-impact-house-races/]//LR

For context, though Republicans currently hold a narrow majority in the House, 224 districts on the 2024 map would have backed Biden in 2020, while Trump would have claimed 211. Using the 2020 results as a baseline for a uniform swing, Table 1 considers two scenarios. The first scenario features a tied national popular vote. Before the debate, Biden was running about even with Trump in FiveThirtyEight’s national poll aggregator. This is the rosier of the two scenarios for Biden, as it assumes he can recover the ground he’s lost since the debate. For this, each district swings about 4.6 percentage points to Trump (a number commensurate with Biden’s actual 2020 two-party popular vote margin). With a tied popular vote, we could expect 10 Biden 2020 seats to flip to Trump, with four more districts being within a few tenths of a point of doing so. Of course, in reality, things likely wouldn’t be as tidy, as some districts would shift more than the national swing while some would see less pronounced, or even leftward, shifts. Considering their marginal nature, it isn’t too surprising that, in terms of their current representation, these 10 hypothetical Biden-to-Trump seats are currently evenly divided between the parties. With the exception of CA-40, where Rep. Young Kim (R) holds a seat that is typically redder than what its presidential topline may suggest, all the GOP-held seats that flip in this scenario are hosting races that the Crystal Ball rates as competitive (we are defining that term to encompass seats that we rate as either Toss-up or Leans Democratic/Republican). First-term Rep. Tom Kean (R, NJ-7) would hold the closest Trump-won seat. As we mentioned last month in our Virginia primary preview, if Biden slips only a few points in our state, we could easily see the Virginia Beach-area VA-2 flipping to Trump, as it does in this case. In Arizona, GOP Reps. Dave Schweikert (R, AZ-1) and Juan Ciscomani (R, AZ-6) both won with less than 51% of the vote in 2022 but would also find themselves in Trump seats. Democrats, meanwhile, would be defending a pair of open, Trump-won seats in Michigan: the adjacent pair of Districts 7 and 8—the former covers the area around Lansing while the latter includes Flint. Two other Democratic-held Great Lakes state seats in this category are OH-13 (Akron) and PA-7 (the Lehigh Valley). While these seats could get tougher for their Democratic incumbents—who both have some of their own strengths—the concurrent Senate races could work in their favor. Sens. Sherrod Brown (D-OH) and Bob Casey (D-PA) will almost certainly run better than Biden in their respective states, and they seem likely to at least carry those types of marginal seats. Finally, in North Carolina, first-term Rep. Don Davis (D, NC-1) was given a tougher seat when the state adopted a new GOP-drawn map last year. In 2022, Davis won his seat (which was bluer than the version he is running in now) by close to 5 points while NC-1’s result in the concurrent Senate race was about even. So a 2.9-point Trump win in his district would not be insurmountable for Davis, although he may not be as well-positioned to outperform the top of the ticket in counties that are newer to him.