One can hardly fault Donald Trump for believing divine providence is on his side. He’s had the most impressive lucky streak in living political memory. 

While his debate performance was exceptional only if graded on a curve, his opponent’s was a debacle by any objective standard. Then the Supreme Court handed down an exceedingly fortuitous ruling on presidential immunity, which at a minimum delayed the federal cases against him until after the election. And a lone concurrence by Justice Clarence Thomas in that decision apparently inspired Aileen Cannon, a federal judge in Florida, to throw out the classified documents case against him.

Oh, and an assassin shot at him and missed. More accurately: almost missed. A bullet sliced through the top of Trump’s right ear; if he had turned his head a millimeter or two in the wrong direction, he would have been dead, and the graphic footage of his murder would now be serving as the backdrop of a dark new chapter of American life.

All of this happened on the eve of the Republican National Convention, buoying the party and consolidating support for Trump’s candidacy. That’s certainly understandable, albeit irrational in a very human way. There’s nothing logical about the idea that being shot by a disturbed young man—and registered Republican—makes Trump more qualified to be president. But it makes emotional sense.

It also deprives President Joe Biden of the central rationale for his reelection, at least for the foreseeable future. Other than abortion rights, “protecting democracy” was going to be the issue Biden rode to reelection. In the current climate, however, attacking Trump as a threat to democracy sounds like extreme rhetoric—as it has been at times. But if Biden can no longer prosecute that case against Trump—after spending tens of millions of dollars on ads laying it out gaining little traction— what case does he have?

Now, I simply reject the idea that criticizing Trump for his attempt to steal the last election or for his own extreme rhetoric is suddenly illegitimate. But political reality is what it is.

What is even more profoundly fortunate for Trump is that the assassination attempt also buoyed Biden’s candidacy, though in a very different way. The Democratic Party is not enthusiastic about Biden. In an NBC News poll conducted shortly before the shooting, only 33 percent of Democrats and Democratic-leaning independents said they were pleased with their party’s nominee, compared with 71 percent on the Republican side. There’s no reason to think the assassination attempt will cause rank-and-file Democrats to rally around Biden.

But what it has done is cause senior Democrats who were determined to push Biden off the ticket to abandon hope and reconcile themselves to losing. “We’re so beyond f—ed,” a “Democratic insider” told NBC News after the assassination attempt. “The presidential contest ended last night,” said another. “[Trump] was already on track to win,” a Democratic Senate aide told Semafor, “and the fact that he is now a victim of political violence rather than the perpetrator undermines Biden’s core appeal.”

I think that analysis is right, but it underscores the necessity that Biden step aside.

Biden’s Oval Office address Sunday was not terrible. It struck a welcome, conciliatory tone, and its shades of unnecessary partisanship were restrained partly because they had to be. Biden is an avatar of the cultural status quo: He ran to restore normalcy and “unify” the country. Whether it’s fair or not to judge him on that score, he failed. And as his interview with NBC’s Lester Holt Monday night demonstrated, his mental fogginess shows he is not up to the job of running for president.

And that’s why the address was a missed opportunity. Biden could have announced that he was standing down as his party’s nominee and in the process tried to pull Trump with him. He could have—and should have—said this country is better than a race most Americans do not want between two grumpy old men who have come to represent two warring tribes. He should have called for turning the page and giving the country a fresh start.

Biden is an unpopular incumbent who is not going to get more vigorous or cognitively acute. And he’s certainly not going to have a viral vitality moment like Trump had Saturday night. 

Simply put, Biden’s luck has run out. But he could still put an end to his opponent’s improbable run of luck.