Recent polls show trouble for President Biden in his re-election bid against President Trump — and should he lose, it could be third-party candidates that deal the final blow.

The election will be decided in swing states, where Mr. Trump now has a slight advantage, according to polls. Yet when third-party candidates are included in these polls, Mr. Trump’s lead in most swing states grows.

In Arizona and Nevada, Mr. Trump’s lead jumps five and four points respectively when the Green party candidate, Jill Stein, and two independent candidates, Robert F. Kennedy Jr. and Cornel West, are added to the polling questions. In Arizona and Wisconsin, Mr. Trump’s lead widens by three points in a five-way race. In Georgia, the third-party candidates have no impact, while in Pennsylvania, they widen Mr. Biden’s lead by four points.

“When it’s close, the third parties have greater impact,” a Democratic strategist, Hank Sheinkopf, tells the Sun. “Ross Perot cost President George Bush the election. Stein probably cost Hillary the election.”

The 2024 ballot is going to be crowded. A former Democrat who is now an independent presidential candidate, Robert F. Kennedy Jr., is getting the most traction among third-party candidates, polling in the high single digits to the teens in swing states. He will likely pull votes from both Messrs. Trump and Biden.

Mr. Kennedy may also seek the Libertarian Party nomination, which would guarantee him ballot access that in “worst case scenario would be 48 states,” the Libertarian National Committee’s chairwoman, Angela McArdle, tells the Sun. Mr. Kennedy’s biggest hurdle to a strong showing in November is ballot access. The Libertarian Party’s nominee will be chosen at its convention in May.

No Labels, which has been working steadily on ballot access for months, may run a “unity ticket” with a Republican and a Democrat in the presidential and vice presidential slots. The chief strategist of No Labels, Ryan Clancy, tells the Sun the group will announce whether it is running a ticket in March. It expects to have ballot access in 50 states.

“Ross Perot at this point in 1982 hadn’t even started gathering signatures yet, and he ended up on all 50 states, so we’re very confident,” Mr. Clancy says.

It will likely be the challengers from Mr. Biden’s left, though, who pose the greatest threat to his re-election. The Green Party candidate, Jill Stein, and independent Cornel West are polling at only about 2 percent, but that may be enough in swing states to hand a victory to Mr. Trump.

The Green Party expects to best its 30-state ballot access from 2020. It’s unclear on how many ballots Mr. West will appear. 

Mr. Biden’s age, his failure to deliver student loan forgiveness, and his staunch support of Israel are driving some progressives, young people, and Muslim Americans — once reliable Biden voters — away from the party. Mr. Biden’s speeches have been repeatedly interrupted by pro-Palestinian protesters in recent weeks. Young Americans — 18- to 24-year-olds — are split on support for Israel, with 60 percent saying Hamas’s actions on October 7 were “justified,” according to a Harvard-Harris poll.  

“The margins are going to be so close in some swing states, and young people are disenchanted,” an anti-war activist and founder of Code Pink, Medea Benjamin, tells the Sun. “The only way to hold Biden accountable for his position of disregarding the lives of so many Palestinian people is not to vote for him.”

In Michigan, a swing state with a Muslim population of more than 200,000, their vote is crucial for a Democratic victory. Mr. Biden won that state by only 155,000 votes in 2020. Mr. Trump won Michigan by similarly small margins in 2016.

Muslim Americans there are now organizing a vote “uncommitted” campaign for the February 27 Democratic primary. The Arab-American mayor of Dearborn, Michigan, Abdullah Hammoud, who supported Mr. Biden in 2020, declined a recent meeting with the president’s campaign manager. Also, in a sign of how concerned the Biden campaign is, senior administration officials are meeting with Arab American and Muslim leaders in Michigan Thursday.  

“This campaign called ‘Abandon Biden’ and the moniker ‘Genocide Joe’ that so many people in my circles are using, the constant interruptions that Biden is experiencing everywhere he goes, I think those are hurting him,” Ms. Benjamin says. “That leaves a flank of the left of the Democratic Party open more towards Jill Stein or Cornel West.”

Mr. Sheinkopf says this poses a “serious problem” for Mr. Biden in Michigan. Yet he doesn’t think Muslim-American voters will flock to Mr. West or Ms. Stein, they just won’t turn out in large numbers. That will also help Mr. Trump. “It will be a significantly larger problem if there’s money put behind Cornel West and Jill Stein,” he says.

Democrats are increasingly worried about the risk these third-party candidates pose to Mr. Biden. No Labels filed a complaint last month with the Department of Justice alleging Democratic operatives are conspiring to thwart its ballot access campaigns. A recent NBC poll found that 34 percent of Americans could see themselves voting for Mr. Kennedy.

After the 2016 election, Ms. Stein was the scapegoat for Hillary Clinton supporters devastated by her defeat. Expect more “a vote for — insert third-party candidate name — is a vote for Trump” campaigns in the coming months. 

Mr. Trump’s favorability rating sits around 42 percent, and he didn’t earn more than 46 percent of the vote in 2016 or 2020. Yet if the Democrats can’t hold their various coalitions together and tamp down third-party support, they may hand this election to Mr. Trump.