Donald Trump built his famed “base” around white working-class voters who felt Washington politicians abandoned them. Yet lifelong Washington politician Joe Biden cornered just enough of those alienated whites to have put him over the top in the 2020 election, making Biden the next U.S. president.

Five days after Election Day, Biden clinched the presidency with at least 273 electoral votes, according to the Associated Press. And in five crucial battleground states—Arizona, Georgia, Michigan, Nevada and Wisconsin—Biden gained ground among white voters without a college degree, according to Edison Research exit poll data analyzed by William Frey of the Brookings Institution. The biggest gains among this group came in Arizona, Michigan and Wisconsin. Biden didn’t win this group outright in any state, but he lost them by a smaller margin than Hillary Clinton did in 2016, accounting for at least part of the gain allowing Biden to flip a few crucial states Trump won by small margins in 2016.

Biden crossed the 270 electoral vote threshold with wins in Pennsylvania, Michigan and Wisconsin, flipping those states blue after Trump carried them in 2016. Biden leads in Arizona, Georgia and Nevada, where tallies still aren’t complete. If Biden holds on to those leads, he’ll beat Trump with 306 electoral votes—equal to Trump’s tally in 2016. Trump claims election fraud, but there’s no evidence and Trump has no path to overturning the election outcome.

Winning more working-class whites was part of Biden’s strategy all along. He continually emphasized his upbringing in hardscrabble Scranton, Pa, along with his support among unions. In day trips to swing states, Biden argued that Trump’s poor handling of the coronavirus and tax cuts that overwhelmingly benefited the wealthy had let working people down.

Apparently it worked. In Wisconsin, Biden’s support improved by 13 points among men without a college degree, and by 11 points among women without a college degree. In Michigan, Biden gained 14 points among lower-educated men and 2 points among lower-educated women. In Arizona, the gain was a whopping 21 points among such men and 3 points among such women. The one state that didn’t budge was Pennsylvania, with essentially no change in the white working-class vote.

Here is Frey’s swing-state data. Each number represents the Democratic share of voters minus the Republican share, allowing comparison of how the margins changed between 2016 and 2020:

Biden had some surprising weaknesses that could have cost him the election, if not for his improvement among working-class whites. He got less of the Black, Hispanic and Asian-American vote than Clinton got in 2016. That’s the main reason Biden lost Florida—despite pre-election polls showing him ahead there—along with Texas, which was never as close as polls suggested.