Who Won the Debate? Biden Stumbles Left Trump on Top

In the first presidential debate of the year between the leading Democratic and Republican candidates, President Biden and former President Donald J. Trump clashed on inflation, taxes, Ukraine and the future of democracy.

A halting performance from Mr. Biden and a relatively steady and measured delivery by Mr. Trump left Democrats deeply concerned about Mr. Biden’s prospects. Personal attacks overshadowed discussions of policy during the debate, with the candidates sparring over who had a better golf game, their respective cognitive abilities and their legal problems.

On cable news and social media, strategists from both parties wondered if Mr. Biden could continue in the race against Mr. Trump. Few Democrats could muster an upbeat assessment of the president’s performance.

Here is a sampling of the reaction.

“It was a really disappointing debate performance from Joe Biden. I don’t think there’s any other way to slice it. His biggest issue was to prove to the American people that he had the energy, the stamina — and he didn’t do that,” Kate Bedingfield, Mr. Biden’s former White House communications director, said on CNN.

“Biden is even whiffing on his easy pitches — abortion and Jan. 6. I mean, my God,” said Matt Gorman, a Republican strategist and former senior adviser to the presidential campaign for Senator Tim Scott of South Carolina.

“Look, I debated Joe 7 times in 2020. He’s a different guy in 2024,” Andrew Yang, a Democratic presidential candidate in 2020, said on the social media platform X, adding the hashtag #swapJoeout.