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

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 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.

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 a Ipsos poll released earlier this month.

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 in the first week of July 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%.

Harris has been on the campaign trail touting Biden's accomplishments and has backed the president since his debate.

"Look, Joe Biden is our nominee. We beat Trump once, and we're going to be him again," she told CBS News earlier this month.

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 earlier this month, defended Biden's debate performance at the time.

"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.

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 reacted to Biden dropping out of the race, but did not indicate whether he'd want to become the nominee.

"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 wrote on X. "He will go down in history as one of the most impactful and selfless presidents."

Newsom pushed back against calls from Democrats for Biden to step down in an interview with MSNBC shortly after the debate.

"I think it's unhelpful and unnecessary," he said. "We have to have the back of this president. You don't turn your back because of one performance. What party does that?"

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 said in a statement reacting to Biden stepping out of the race, "While his decision today could not have been easy, it is in the best interest of our country, and our party. I want to thank him for his leadership, kindness and for a successful presidency that got big, important things done."

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

"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 that Biden will be the Democratic nominee "unless he makes some other decision."

Pritzker also released a statement after Biden exited the race, but did not indicate he wanted to step into the race.

"Perhaps most consequentially, President Biden restored dignity to the Oval Office, bringing the statesmanship and honor that have been the hallmarks of his years of service, back to the White House," he said.

Prior to Biden exiting the race, Pritzker said in a statement: "For me anyway, my word is my bond. I honor my commitments. Joe Biden is going to be our nominee unless he decides otherwise. I think that there's a healthy conversation that will happen with the president, I hope, expressing what he intends to do going forward in the campaign and reassuring everybody that this is the right course."

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.

He dismissed calls to remove Biden from the ticket during an interview with MSNBC Friday.

"Joe Biden is our candidate and our president because he is the best person to lead this country forward," he said.

Michelle Obama

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