Anew poll has found Vice President Kamala Harris is the top choice to replace President Joe Biden should he abandon his reelection campaign. Biden’s recent shaky debate performance has led some Democrats to consider whether he should be replaced on the ballot before November.

The Biden campaign has said the president is not dropping out. If he did, Harris, his vice president and running mate, would most likely join other top Democrats looking to replace him at the top of the ticket. A Date for Progress flash poll, conducted on Friday, found Harris was the most popular choice to replace Biden. The poll surveyed 1,011 U.S. likely voters, including 387 Democratic likely voters, and has a margin of error of 3 percentage points.

Asked who should be picked if the Democratic Party holds a convention among party members to choose a replacement for Biden, 39 percent of Democrat respondents chose Harris.

The Biden campaign has been contacted for comment. Seth Schuster, a Biden campaign spokesman, previously told Newsweek: “Joe Biden is not dropping out.”California Governor Gavin Newsom was the second most popular option, with 18 percent of Democrats picking him as their choice to replace the incumbent.

Transportation Secretary Pete Buttigieg got 10 percent of the vote, Senator Cory Booker received 7 percent and Michigan Governor Gretchen Whitmer got 6 percent.

Senator Amy Klobuchar, Illinois Governor J.B. Pritzker, and Pennsylvania Governor Josh Shapiro each garnered only 2 percent.

Another 6 percent said their choice would be someone not on the list, while 9 percent said they were not sure.

“The real problem with swapping out Biden is that Democrats will be venturing into the great unknown,” Thomas Gift, an associate professor of political science and director of the Centre on U.S. Politics at University College London, told Newsweek.

“Although there may be an alternative with a larger potential upside, a Biden replacement is just as easy to take a beating in his or her favorability after being vetted on the national scene.”

A Morning Consult poll conducted after Thursday’s debate also found that 47 percent of Democratic voters and 59 percent of independent voters think Biden should be replaced as the Democratic Party’s presidential candidate.

Biden responded to critics at a rally in North Carolina on Friday.

“Folks, I don’t walk as easy as I used to. I don’t speak as smoothly as I used to. I don’t debate as well as I used to. But I know what I do know: I know how to tell the truth. I know right from wrong. And I know how to do this job,” he said. “I would not be running again if I didn’t believe with all my heart and soul I can do this job.”

Elaine Kamarck, a senior fellow at the Brookings Institution think tank, a Democratic National Committee member, and author of the book Primary Politics about the presidential nominating process, told Reuters that there are several scenarios regarding how Biden could be replaced as the Democratic Party’s presidential candidate.

Biden could decide to step aside before he is officially nominated at the convention in August, she said. He could also be challenged by others who try to win over the delegates he has accrued, or he could withdraw after the convention, leaving the DNC to elect someone to run against Donald Trump, the presumptive Republican nominee, in his place.