Last night, as President Trump spoke, the votes were being tallied in a big Republican win in a special election in Minnesota.

Granted, it wasn't anything earth-shattering. Jason Rarick, a Republican member of the state House, picked up a state Senate seat in the 11th district (the northeastern part of the state) that had been represented by Democrats for two generations — which is to say that Democrats from two generations of the Lourey family had held the seat since 1996. Stu Lourey, the scion of this clan, proved unable to keep it in Democratic hands after his dad was tapped to serve in the administration of Democratic Gov. Tim Walz.

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The final count wasn't close — the Republican Rarick won by eight points, increasing the Republicans' narrow majority in Minnesota's state Senate to three seats. Try as he might, the young Lourey, former aide to the disgraced former Sen. Al Franken, could not overcome the same political forces of realignment that helped put Iowa, Ohio, Wisconsin, and Michigan into Trump's column in 2016 and nearly put Minnesota into it as well.

To be sure, this victory is but a small consolation for Republicans, who did very poorly in Minnesota elections in 2018 (except, ironically, at the U.S. House level, where they were being blown out in most of the country). But it's a big deal in a different way.

We've seen how some parts of the U.S. — suburban Dallas, Atlanta, and Phoenix, for example — have trended toward Democrats in the Trump era. But this district provides an important counterexample. This is the kind of area trending in the opposite direction: an Upper Midwestern region, represented for decades by Democrats, but rapidly trending red, and where Trump won in 2016 by double digits.

Minnesota is going to be a key state in the 2020 presidential election. Trump very nearly carried it in 2016, and there exist several electoral college scenarios in which the Gopher State provides the winning margin. You can bet anything that districts like this one will be major battlegrounds for both parties, every bit as much as the Southern suburban areas where Democrats hope to shift the map in their favor.