Who will replace Joe Biden as presidential nominee? Kamala Harris does best against Trump in polls

WASHINGTON -- With President Joe Biden announcing he will step down as the Democratic nominee this election, some voters already have indicated their preferences for potential successors on the ticket.

Kamala Harris

Vice President Kamala Harris is seen as a likely top contender, according to polling after the first presidential debate, where Biden gave a poor performance.

In announcing he was stepping down, Biden endorsed Harris for the Democratic nominee for president.

"Today I want to offer my full support and endorsement for Kamala to be the nominee of our party this year. Democrats - it's time to come together and beat Trump. Let's do this," Biden wrote.

Harris also posted to social media saying, "On behalf of the American people, I thank Joe Biden for his extraordinary leadership as President of the United States and for his decades of service to our country. I am honored to have the President's endorsement and my intention is to earn and win this nomination."

"I will do everything in my power to unite the Democratic Party and unite our nation to defeat Donald Trump and his extreme Project 2025 agenda. If you're with me, add a donation right now," she added.

In a potential matchup between Harris and former President Donald Trump, Harris and Trump were nearly tied with 42% supporting her and 43% supporting the former president, according to an Ipsos poll released after the presidential debate between Biden and Trump.

The same poll, which interviewed 1,070 registered voters nationwide and had a margin of error of +/- 3.5%, found that Biden and Trump each had 40% support.

Another poll released by CNN found that a matchup between the vice president and Trump resulted in a 45-47% split between Harris and Trump compared to the 43%-49% split between Biden and Trump.

The CNN poll sampled 1,274 registered voters and had a margin of error of +/- 3.5%.

Gretchen Whitmer

Michigan Gov. Gretchen Whitmer, who won reelection in 2022, has been seen as a potential 2028 Democratic presidential candidate. She has pushed back against Republican critics including Trump, particularly ones who criticized her pandemic policies.

The Ipsos poll had Whitmer trailing Trump 36% to 41% in a 2024 race while the CNN poll had her 42% to Trump's 47%.

Whitmer, who attended a meeting at the White House with the president and other Democratic governors at the beginning of the month defended Biden's debate performance in a statement.

"Joe Biden is running to serve the American people. Donald Trump is running to serve Donald Trump. The difference between Joe Biden's vision for making sure everyone in America has a fair shot and Donald Trump's dangerous, self-serving plans will only get sharper as we head toward November," she said.

After Biden's announcement, she posted on social media, "My job in this election will remain the same: doing everything I can to elect Democrats and stop Donald Trump."

Gavin Newsom

California Gov. Gavin Newsom has been a staunch Democrat on several national issues, including women's rights, immigration and the economy. He successfully won a recall election last year.

In the Ipsos poll, Newsom fared 39% to Trump's 42% and in the CNN poll he received 43% to the former president's 48%.

Newsom has been among Democrats who pushed back against calls for Biden to step down.

He posted on social media Sunday, thanking Biden for his work as the 46th president.

"President Biden has been an extraordinary, history-making president - a leader who has fought hard for working people and delivered astonishing results for all Americans. He will go down in history as one of the most impactful and selfless presidents," he said.

Newsom also endorsed Harris Sunday night, caller her tough, fearless and tenacious.

"With our democracy at stake and our future on the line, no one is better to prosecute the case against Donald Trump's dark vision and guide our country in a healthier direction than America's Vice President, @KamalaHarris," he posted on X.

Andy Beshear

Kentucky Gov. Andy Beshear has been viewed as a rising star in the south after he won reelection in the deep red state last year.

The Ipsos poll showed a Beshear-Trump match-up would result in a 36%-40% split between him and the former president. The CNN poll did not survey respondents about Beshear being a potential successor.

Beshear previously said he did not want to talk about the speculation during an interview on CNN.

"My name coming up, it's flattering as a person to hear, but I think it's more about the good things going on in Kentucky," he said. "And so while it's nice to hear your name and things like that, I'm just proud of what we have done as a state. And the president and the vice president have been very helpful in making a lot of that happen."

J.B. Pritzker

Illinois Gov. J.B. Pritzker has been a vocal Biden surrogate from the beginning of the 2024 campaign and has constantly criticized Trump over his far-right policies, rhetoric and his criminal conviction.

The Ipsos poll found that 34% of voters would choose Pritzker if he were on the ticket versus 40% for Trump. Pritzker's name wasn't floated by CNN's pollsters, however, he told the network last month that Biden will be the Democratic nominee "unless he makes some other decision."

"President @JoeBiden has dedicated his life in service to this nation, and its citizens are all better for it. His is a storied political career culminating in one of the most accomplished and effective presidents of our lifetime," Pritzker posted on X after Biden's announcement on Sunday.

Pete Buttigieg

Transportation Secretary Pete Buttigieg was one of the rising stars of the 2020 Democratic primary season both on the campaign trail and in debates.

The former South Bend, Indiana, mayor was a major surrogate for Biden in 2020 after he bowed out of the race, going on several media appearances to tout Biden's record and call out Trump's performance.

In the CNN poll, 43% of respondents picked Buttigieg compared to 47% for Trump. Ipsos did not float Buttigieg as a potential candidate in their poll.

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He previously dismissed calls to remove Biden from the ticket but has since said he is "thankful for [President Biden's] unwavering focus on what is best for our country."

Michelle Obama

Former first lady Michelle Obama has repeatedly said she has no interest in entering the presidential race for years. Her name, however, keeps coming up as a potential candidate.

"At no point have I ever said, 'I think I want to run.' Ever," Michelle Obama said in a 2023 interview with Oprah Winfrey. "Politics is hard. And the people who get into it, it's just like marriage, it's just like kids, you've got to want it. It's got to be in your soul, because it is so important. It is not in my soul."

However, in the Ipsos poll, the former first lady appeared to strike a chord with some voters.

Michelle Obama led Trump 50% to 39%.

ABC News' Oren Oppenheim and Brittany Shepherd contributed to this report.