From the article, “Why Trump Can't Afford to Lose,” by Jane Mayer, and published on the New Yorker site several days before the election:

If the winner's advantage in the Electoral College is decisive, neither side will be able to easily dispute the result. But several of Trump's former associates told me that if there is any doubt at all—no matter how questionable—the President will insist that he has won. Michael Cohen, Trump's former attorney, told me, “He will not concede. Never, ever, ever.” He went on, “I believe he's going to challenge the validity of the vote in each and every state he loses—claiming ballot fraud, seeking to undermine the process and invalidate it.” Cohen thinks that the recent rush to confirm Amy Coney Barrett to the Supreme Court was motivated in part by Trump's hope that a majority of Justices would take his side in a disputed election. ...

“He'll blame everyone except for himself,” Cohen said. “Every day, he'll rant and rave and yell and scream about how they stole the Presidency from him. He'll say he won by millions and millions of ballots, and they cheated with votes from dead people and people who weren't born yet. He'll tell all sorts of lies and activate his militias. It's going to be a pathetic show. But, by stacking the Supreme Court, he'll think he can get an injunction. Trump repeats his lies over and over with the belief that the more he tells them the more people will believe them. We all wish he'd just shut up, but the problem is he won't.”

On cue:

How much more can he muck up the system? I don't know. On the plus side, his lawyers are “not exactly the A-Team,” in the words of LA attorney Ted Boutros, who is a member of the A-Team. On the downside, thanks to Mitch and the Federalist Society, he's packed the courts with partisan, lesser lights. Plus there's the damage he does to democracy with his accusations—the fury he'll provoke to get what he wants. I also don't know if he's going to jail. That's the second half of the article. But I do know this: I'm tired of crazy, and Trump is motherfucking crazy.