Can Democrats replace Biden as their nominee?

That President Joe Biden, age 81, is an elderly man is nothing new.

But the first presidential debate between Biden and former President Donald Trump Thursday night has pushed the question of Biden’s age to the top of the public’s consciousness. His verbal stumbles, weak voice (the campaign has said that he was dealing with a cold) and meandering responses to Trump’s jabs and the moderators’ questions are likely to bring up one question: Is there any way Biden could be replaced as the Democratic Party’s presidential nominee?

The short answer is, practically, there probably isn’t. All 50 states have already held their primaries, and Biden has won the vast majority of their delegates. Only Biden himself can direct those delegates to vote for someone else, as they are pledged to vote for him unless he drops out before the Democratic convention this August.

This is where practical and political challenges merge: Biden is the only one who can decide if he wants to drop out before the floor vote. No secretive party apparatus or individual can direct him to do it.

And unless Biden has a serious change of heart after Thursday night, there are plenty of reasons that wouldn’t happen.

The first obstacle: Presidents are chosen through elections between candidates picked through a specific, organized party process.

The Democratic presidential nominee is chosen in August at the Democratic National Convention in Chicago, where a candidate needs to win the support of the majority of the Democratic delegates. Those delegates are assigned proportionally based on the vote totals in a state’s primary (for any candidate who wins more than 15 percent of votes) and are then “pledged” or “bound” to that candidate in the first round of voting at the Democratic convention. Under this system, some other candidate would need to win more delegates than Biden in order to become the nominee.

But Biden has not just all the delegates he needs, but essentially all the delegates, period. So practically, there isn’t anyone that could be swapped in at this point.

And according to DNC rules, these delegates are bound to support Biden during the first floor vote of the DNC.

Beyond the limits set by that process, there are also practical financial hurdles: Only Biden has the fundraising and money machine necessary on the Democratic side to run ads, hold events, hire staff, and, effectively, run a campaign. No other Democrat, elected or unelected, has that practical machinery in place.

At this point, it’s also politically risky for anyone to try to publicly force Biden out.

The Democratic establishment has already united around Biden — endorsing him, stumping for him, and leading the party’s operations not only because he is the incumbent, but because it’s him specifically. They have deep relationships with him and are loyal to him.

This is also where it’s important to dispel the notion that anyone could force Biden to drop out.

The DNC is not some omnipotent, shadowy operation that has the power, influence, or ability to crown a different party leader. Who do you think chose the DNC chair and vice-chairs? Biden! There just isn’t a council of decision-makers who can tell Biden to drop out or choose to ditch him.

The power of party elites is often overstated, and the primaries so far show the influence of voters. As unpopular as Biden might seem to some folks, he still won handily in the 2020 primary, and when given options to protest-vote in New Hampshire or select “none of these candidates” in Nevada this year, Democrats have still sided with Biden.

And all the leading figures who could replace him — Michigan Gov. Gretchen Whitmer, California Gov. Gavin Newsom, Pennsylvania Gov. Josh Shapiro, maybe even Maryland Gov. Wes Moore (let alone Vice President Kamala Harris) are all major public surrogates and supporters of Biden. They wouldn’t publicly turn on him now. And it’s not clear that they would privately try to force him out. Even at the most self-interested level, none of them has an incentive to let the other strongarm a Biden capitulation.

So only Biden could make the decision to drop out. He doesn’t want to (not least because he sees himself as key to stopping Trump’s reelection). And even if he did choose to, the only option that would not risk massive dissension among the Democratic base would be to choose his vice president, Kamala Harris. The vice president has her own political drawbacks: She polls worse than Biden against Trump, has never run a successful national campaign, and, unfortunately, faces different voter prejudices because she is a woman of color.

Other polls also show similarly negative results for Whitmer, Shapiro, and Newsom. They have polled worse than Biden, or are biding their time. And to bypass Harris for one of them also opens up potential ire from Black voters, without whom Democrats can’t win.

Should another Democrat savior emerge, with the vocal support of someone like Barack Obama and a core of Biden-critical strategists and politicians, and should first lady Jill Biden and other Biden confidantes approach Biden and convince him to drop out, we’d likely head toward a brokered convention with multiple rounds of voting. That also opens up the chance for even more chaos and disunity among Democrats. Does that seem worth it to anyone in Democratic politics right now?

At least until Thursday night, the answer was simple: No. It’s too late.