Michigan representative Elissa Slotkin was supposed to be one of the House’s most embattled incumbents. A Democrat representing a district that Joe Biden narrowly won, Republicans flooded her district with millions, making it the most expensive House race in the country, thinking Slotkin would be low-hanging fruit in their expected red wave. Instead, when election day came, Slotkin won, and she won fairly easily — besting her opponent by a comfortable 5 points.

It wasn’t just Slotkin, though: across the industrial Midwest, Democrats turned in some of their most impressive performances, swamping Republicans, flipping legislatures, and knocking out supposedly safe Republican incumbents. John Fetterman and Josh Shapiro romped in Pennsylvania, while Democrat Marcy Kaptur held on and Republican Steve Chabot was bounced in Ohio. Michigan Democrats won a governing trifecta, and Pennsylvania Democrats believe they won the state House for the first time in more than a decade. Democratic governors in Minnesota and Wisconsin sailed to reelection.

Some of their success is no doubt attributable to backlash against the GOP for overturning Roe v. Wade and the slate of election-denying wackos Republicans put up across the country. But no theory of the midterms can really hold up without accounting for why Dems were so unusually strong in the Midwest — in states with large blue-collar populations that seemed at risk of drifting away in the Donald Trump era.