Daily Kos Elections recently completed calculating the 2016 presidential election results by congressional district. With ticket-splitting rates at historic lows, and presidential results highly correlated with congressional results, these numbers serve as a strong predictor of future House election outcomes. As Democrats seek to gain the 24 seats they need for a majority and defend the 194 they currently hold, these 21 districts that flipped to Donald Trump after supporting President Obama in 2012 could become increasingly difficult for Team Blue to win in upcoming elections.
As shown on the map above (see here for a larger image), Nevada’s 3rd is the only one of these districts that isn’t located in the Northeast or Midwest, which were two regions where Trump performed considerably better than recent Republican nominees. Most of these seats are heavily white, disproportionately rural, and have much lower rates of adults holding college degrees than the national average. Those three demographics became much redder in 2016 compared to 2012, even as college-educated white voters voted more Democratic.
Trump did very well in many of these districts, even capturing five that President Obama had carried by more than 10 points, while Trump himself won seven of these Obama seats by double digits. Democrats might be fortunate that they only hold nine of these 21 districts, simply because it limits their exposure. Team Blue prevailed by just single-digit margins in six of these races, and three Democrats even hold seats that Trump won by more than 10 points. Accordingly, these nine Democrats could be especially vulnerable in 2018 if downballot voting aligns more strongly with the presidential outcome.
You can find a chart of all 21 districts that flipped from Obama to Trump below. Be sure to check out our previous maps and analysis of the presidential and congressional results for all the districts, and also our Congress guide spreadsheet, which compiles those results along with demographics and member information for every seat.
Obama’s best district that Trump flipped was Illinois’s 17th, located in the state’s northwest corner. The former president prevailed there by 17 percent in 2012, but Trump narrowly took the district by just under a point, a reversal of almost 18 points. Democratic Rep. Cheri Bustos had considered a run for governor, which would have made it much tougher to hold her seat, but the DCCC was able to breathe a sigh of relief when she said this week that she’d seek re-election instead.
Trump’s best seat that Obama had carried four years earlier was Minnesota’s 8th District, based around the Iron Range in the state’s northeast. It voted for Trump by a 17 percent landslide, marking a staggering 21-point lurch to the right from 2012, when Obama secured a 6-point margin of victory. Democratic Rep. Rick Nolan survived by an incredibly narrow margin, and he’s likely to be targeted again. Nolan, too, is contemplating a bid for governor, but Democrats will have a hard time defending his seat even if he seeks another term in the House.
You can see all of the Obama-Trump districts in the chart below.