How Kamala Harris Performs Against Donald Trump in the Polls

This is an improvement over Mr. Biden’s standing in the race: When he announced that he was ending his campaign on Sunday, he trailed Mr. Trump by three percentage points in The Times’s national polling average, 47 percent to 44 percent.

In recent swing state polls, taken before Mr. Biden announced he would withdraw from the presidential race and completed before the assassination attempt on Mr. Trump, Ms. Harris was only down by a percentage point in the crucial swing state of Pennsylvania in a hypothetical matchup with Mr. Trump. And she was winning by a more comfortable five percentage points in Virginia, a state where Mr. Biden was up by only a razor-thin margin.

In both states, Ms. Harris performed slightly stronger than Mr. Biden with Black voters, younger voters, and women — all groups that Democrats need in order to be successful this fall. And, importantly, those are groups where Mr. Biden appeared to be losing ground.

As recently as April, Ms. Harris was polling substantially behind Mr. Biden’s standing, but she has gained ground in recent surveys.

At the same time, increasing shares of Democrats had said that they wanted Mr. Biden to step aside. In an AP-NORC poll conducted between July 11 and July 15, nearly two-thirds of Democrats said they wanted the president to withdraw and allow the party to select a different candidate. On Sunday, they got their wish.