A trio of bellwethers

The fall midterms will be fought in thousands of towns and cities nationwide. But if you want to get a quick idea about the outcome, go to Miami, Minneapolis, and Philadelphia. Together these areas include 13 in-play House seats and contain concentrations of the types of voters up for grabs in other places.

Miami-Dade County is dominated by Latin Americans, especially those of Cuban heritage. It normally votes Democratic in presidential races, but it currently sends three Cuban-American Republicans to the House. That’s because Cuban immigrants have long voted Republican due to the party’s traditional opposition to the island’s Communist regime. But younger Cubans have no memories of the old land and vote much more for Democrats. Miami-Dade also has large numbers of recent émigrés from throughout Latin America: These voters are staunchly Democratic.

Together, these trends make it likely that two of the GOP-held seats will flip parties and have placed the third, Mario Díaz-Balart’s 25th district, under severe pressure. If Latinos turn out in large numbers and vote as they did in 2016, they could flip Díaz-Balart’s seat—which Trump narrowly carried—and reelect Democratic Sen. Bill Nelson, who is facing a tough challenge from the current Republican governor, Rick Scott.

Minneapolis is thought of as a very liberal, Democratic area. That is true for the inner cities, but the suburbs send two Republicans to the House. Both face serious challenges: One, Erik Paulsen, represents a seat that Hillary Clinton won by 9 percent in 2016 but that supported Barack Obama by less than a point in 2012. It’s no accident therefore that Paulsen’s first television ad emphasizes that he opposes Trump when he thinks Trump’s acts will hurt Minnesotans. These “Romney-Clinton” voters exist throughout affluent suburbs nationwide: If they don’t come home to the GOP, Republicans will be very hard-pressed to hold the House.

Outside Minneapolis, but still within the Twin Cities’ media market, are two totally different House districts, the 1st (Rochester) and the 8th (Duluth). Each of these seats is currently held by a Democrat who is not running for reelection. Both districts went for President Obama in 2012 but went overwhelmingly for Donald Trump in 2016, and these “Obama-Trump” voters, largely whites who did not graduate from college, are the reason Trump is in the White House. Republicans think they can pick up both seats, but to do so they must transform these voters’ allegiance to Trump into support for the GOP. If they can, Republicans could hold on to similar seats already represented by Republicans and pick up enough seats from Democrats to offset losses in Hispanic or suburban areas. If they cannot, Election Day might be very dark for the GOP.

The Philadelphia media market will be ground zero for control of the House. Six seats held by Republicans are under threat there. Redistricting placed two beyond the GOP’s reach while failure to recruit a good candidate has made a third a sure Democratic pickup. That leaves three seats, each of which was either narrowly carried by Trump (New Jersey’s 3rd) or Clinton (Pennsylvania’s 1st and 7th), as the prizes to be won. Each seat has a mix of both types of swing voters, the “Romney-Clinton” and the “Obama-Trump,” and the results here will be a good bellwether for the nationwide outcome.

In every race the individual candidates matter, so if someone commits a serious gaffe or has unusually strong grassroots support, that candidate could stand apart from national trends. But as a general matter, Democrats need to pick up at least eight of these 13 seats to retake the House and must retain Florida’s Senate seat to have a shot at winning that chamber. The outcomes in these three areas on election night will likely tell us a lot about the outcome once all the votes are counted.