(NewsNation) — President Joe Biden and former President Donald Trump are about even in head-to-head polls, but Biden suffers more when third-party presidential candidates are included in surveys, according to a new Wall Street Journal analysis.

A recent NBC News poll showed Biden and Trump tied at 46% support in a 2024 head-to-head matchup. But when voters were offered the Green Party, the Libertarian Party and the group No Labels as options, Biden lost 10 percentage points, whereas Trump lost seven.

It’s a sign the contenders from outside the two major political parties could have a significant impact on the upcoming election.

Those candidates include Robert F. Kennedy Jr., Jill Stein and Cornel West.

Back in 2016, Libertarian Party nominee Gary Johnson received over 3.2% of the vote, which was the highest nationwide vote share for a third-party candidate since Ross Perot in 1996.

Green Party nominee Jill Stein earned more than 1% of the vote share in 2016. She announced her bid for the White House this week.

Polling suggests more Americans than ever are open to a third-party candidate, but experts say those surveys can be misleading.

“It’s very easy to tell a pollster: ‘Oh sure, I’m gonna vote for RFK Jr. or Cornel West or Jill Stein or whoever is running,'” said Allan Lichtman, a history professor at American University. “But once you get into the polling booth, there is something called the wasted vote syndrome.”

That feeling, Lichtman says, drives people to choose candidates with a good chance of winning.

It’s still unclear whether West Virginia moderate Democrat Joe Manchin will throw his hat in the ring.

Earlier this week, Manchin announced his decision not to seek reelection for his Senate seat, heightening speculation that he could enter the presidential race.

“What I will be doing is traveling the country and speaking out to see if there is an interest in creating a movement to mobilize the middle and bring Americans together,” Manchin said.