Here’s What’s Keeping Democrats Up at Night Ahead of the Debate

After weeks of Democratic exuberance surrounding Vice President Kamala Harris’s sudden rise to the presidential nomination, the party’s joyous August has given way to a season of anxiety, as it braces for another nail-biter against former President Donald J. Trump.

Asked what should be keeping Democrats up at night, Patrick Murray, who directs the polling institute at Monmouth University, replied bluntly, “They could lose.”

That outcome seemed nearly a guarantee before President Biden bowed out of his re-election bid late this summer, Mr. Murray said. Now, he added, the election is merely a “close race, as opposed to a race that you’re almost certain to lose.”

A national poll of likely voters by The New York Times and Siena College released on Sunday found Mr. Trump leading Ms. Harris by 48 percent to 47 percent, within the poll’s three-percentage-point margin of error.

On the eve of the only scheduled debate between Ms. Harris and Mr. Trump, here’s a look at a few of the main worries emerging for Democrats, based on interviews with pollsters, party strategists and elected officials:

Before Mr. Biden dropped out, he appeared stunningly weak among vital groups of Democratic-leaning voters, including Black, Hispanic and younger Americans.