Unemployment is abnormally low. Growth has sped up. A $1.5 trillion tax cut, signed by President Trump last year, is fueling consumer spending. Faced with strong Democratic enthusiasm and fund-raising, and hindered by an unpopular president, Republicans were counting on that economic strength to lift them at the polls, or at least limit the damage.

It didn’t. Republicans lost in House districts with low unemployment rates. They lost in districts that have gained manufacturing jobs. They lost in districts that got big tax cuts. And they lost overwhelmingly in the kind of affluent, educated suburbs that have experienced the strongest overall recovery — and that were once among the most reliable Republican districts.

Republicans had lost 30 net seats in the House as of Friday afternoon, and will probably lose a few more once all the votes are counted. It is possible, of course, that Republican losses might have been even larger were it not for the strong economy. But there was little sign of that in district-level results: Many of the Democrats’ pickups came in places where the economy, at least by standard measures, is strong.

All told, there was no apparent relationship between Republican candidates’ performance in Tuesday’s House races and the strength of the economy in those districts, an analysis of economic and electoral data shows.