WASHINGTON — The debate was always going to be a gamble for Joe Biden — but the bet may prove more costly than he imagined after he gave what was roundly panned as a bumbling and incoherent performance.

Alarmed by the spectacle, some Democrats fretted that they might need to dump Biden from the ticket, even as his campaign aides insisted that nothing about the evening should disqualify him as a candidate.

Heading into the debate, Biden’s advisers believed that once voters got a close look at the unfiltered Donald Trump — once they heard his outbursts and taunts — they’d appreciate Biden’s steadiness and realize they had no choice but to give him another term.

So they pitched a debate months earlier than usual, and Trump accepted.

Minutes in, the plan seemed to have backfired.

Biden gave a shaky performance, speaking in a hoarse voice that at times trailed off into incomprehensibility. In split-screen shots, Biden kept his mouth agape while he was listening to questions and answers, a contrast to his opponent’s look of cold determination.

After he discussed the social safety net, he inexplicably pronounced, “We beat Medicare,” the popular program that provides health care to older Americans.

“He did beat Medicare; he beat it to death,” Trump replied.

Watching the performance, Biden’s advisers were initially worried. They said his hoarseness stemmed from a cold. But they hadn’t prepared viewers by explaining his condition in advance, making Biden’s delivery all the more jarring.

Even Biden’s former communications director Kate Bedingfield said afterward that “it was a really disappointing debate performance from Joe Biden.”

The mood inside Biden’s campaign offices brightened as he gradually gained footing and his voice grew stronger. Aides said Biden delivered a few choice lines that they plan to circulate widely through social media, notably when he said of Trump: “Only one of us is a convicted felon, and I’m looking at him.”

Of Biden’s rocky start, one of his aides said: “He just needed to warm up.” 

“Not an ideal start,” another conceded while insisting there was “no mass panic” at the campaign headquarters in Wilmington, Delaware, about his performance overall.

Biden’s team was heartened as it conducted a private test of what average viewers thought about the debate in real time. Voters register their reactions to what the candidates say by turning dials in one direction or another. 

Several campaign sources said voters reacted negatively to a number of Trump’s answers, including his defense of his actions on Jan. 6, 2021, when his supporters stormed the U.S. Capitol and interfered with Congress’ counting of the electoral votes certifying Biden’s 2020 victory.

Other answers Trump gave may well alienate independent voters, Biden aides said. They mentioned that voters recoiled at some of Trump’s insults, including when he called Biden “the worst president in the history of our country.” 

Biden smiled at that. Historians rated Trump as the worst president in history this year, which Biden made a point to mention.

Another bright spot for Biden’s campaign was its fundraising haul — which aides touted in the hours leading up to the debate. An aide said the campaign reeled in more donations Thursday than on any other day in the election cycle, though the person wouldn’t disclose the total.

With Biden’s stumbles fresh in people’s minds, some Democratic strategists, elected officials and opinion-makers began openly calling for him to drop out of the race.

Nicholas Kristof, an influential New York Times columnist, wrote on X that Biden should “reflect on this debate performance” and withdraw in favor of Michigan Gov. Gretchen Whitmer, Biden’s commerce secretary, Gina Raimondo, or another candidate who would be better positioned to defeat Trump.

That’s not likely to happen, and the mechanics of removing Biden against his will are difficult for a Democratic Party that has gone all-in on his re-election.

Biden aides stressed that whatever happened on the debate stage, the fundamentals of the race are unchanged. The election remains a choice between what they see as a successful and stable sitting president versus Trump, who poses a threat to American democratic norms built up over more than two centuries.

In the coming days, they hope, voters will remember the stakes and overlook Biden’s stumbles. 

“Biden’s voice has been raspy, but voters shouldn’t let that distract them from Trump’s endless stream of lies and anger,” a Democratic officeholder and Biden ally said. “Trump is attacking women and immigrants and offering nothing positive for our future.”

It’s evident, though, that Team Biden’s bet on the debate didn’t pay off as planned. What it wanted to see was the confident and forceful Biden who gave a commanding performance during his State of the Union address in March. That’s not who showed up in Atlanta on Thursday.

“I was expecting State of the Union Joe,” said a member of Biden’s fundraising team.