Trump needed a huge drop in turnout to win and that’s exactly what happened.

There was some method to all the madness. The constant and vicious attacks on Hillary Clinton, the seemingly nonsensical appeals to Bernie Sanders supporters, the unending debasement of the norms of American democracy. If turnout hit 2008 levels or 2012 levels, Trump would almost certainly lose. But if it fell, he had a shot. And it fell. Turnout on election night was lower than it has been since 2000, and Clinton lost in key states—Pennsylvania, Michigan, Wisconsin—by razor-thin margins.

Clinton will almost certainly win the popular vote, but she will ultimately receive significantly fewer votes than Obama did in 2008 or 2012.

There will be a lot of talk over the next few days about which groups are to blame for Trump’s rise (white people), and what the election’s surprising demographics mean (Trump appears to have done much better with blacks and Hispanics than expected). But right now, hours after making a world-historical mistake, one very simple thing stands out: Trump won in large part because millions of people did not vote.