What if Jill Stein or RFK Jr. decides the election?

In several swing states, the 2024 election polls are practically tied. The slightest factor could impact the results either way — including the presence of a third-party candidate on the ballot. 

Third-party candidates don’t tend to get much traction: Without a major party behind them, every step of the electoral process is decidedly more difficult, including building name recognition, earning endorsements, getting on the ballot or a debate stage, and fundraising. 

But third-party candidates don’t need much support to disrupt a race. In the last two election cycles, the average number of votes that decided the results in the seven swing states was less than 125,000 votes. In Wisconsin, for example, the election went Trump’s way by 22,748 votes in 2016 and Biden’s by 20,682 in 2020 — an average margin of victory of less than 21,715 votes. And while any one third-party candidate is unlikely to crack that threshold alone, votes for all third-party candidates combined have well surpassed that threshold in some states. 

Kyle Kondik, managing editor of Sabato’s Crystal Ball at the University of Virginia Center for Politics, said that this year, the third-party vote share is likely to be closer to what it was in 2020 (about 2 percent) than what it was in 2016 (about 6 percent). That might be in part because 2016 saw an unusually large share of Americans dissatisfied with their options for president, and Harris’s entry into the race to replace President Joe Biden this year appears to have given most Democratic-leaning voters a candidate they can get behind. 

Still, Kondik said it’s “possible, if not likely, that the total third-party share will be bigger than the margin between Trump and Harris in one or more states.” 

That means that third-party voters, notoriously unpredictable and difficult to persuade, could play a decisive role in a very close election, swinging it in either Trump’s or Harris’s direction. 

Who are the third-party candidates on the ballot? 

There are a few key third-party candidates to know. None of them is very popular, but together, the top four are polling at about 3 percent nationally. (Notably, most polling averages and models have Harris and Trump within 2 percentage points of each other).

Chief among the third-party candidates who made it on swing-state ballots this year is the Green Party’s Jill Stein, a progressive who drew Democratic-leaning voters in her previous two presidential bids.

Stein is on the ballot in every swing state except Nevada, and she’s been backed by a Muslim American group called “Abandon Harris” in Michigan. The vice president is struggling among Arab-American voters there who helped power Biden’s 2020 victory in the state and who oppose the Biden administration’s approach to the war in Gaza.

Both Stein and the Libertarian Party nominee Chase Oliver each claim about 1 percent support nationally, according to recent New York Times polling. That’s less than Stein’s vote share in 2016, when she last ran for president. 

Still, it could be enough to upset the results in the same states where she’s previously earned significant numbers of voters: In 2016, she earned more votes in the “Blue Wall” states of Michigan and Wisconsin than Trump’s margins of victory in those states.

Another potential wild card in those states is independent Robert F. Kennedy Jr., who suspended his campaign and endorsed former President Donald Trump in August.

Given his embrace of the anti-establishment views held by certain segments of the GOP and his status as a member of the Democratic Kennedy dynasty, he was once seen as a potential spoiler for both Trump and President Joe Biden. Kennedy was polling around 10 percent nationally for the better part of 2024, and even higher in some swing-state polls. But his support cratered to less than 5 percent in August after Harris assumed the Democratic nomination, suggesting that many Democrats saw him as the only alternative to Biden and were not particularly invested in his candidacy.

Now, he has more potential to be a spoiler for Trump. He’s recently polled at about half a percentage point, on par with independent Cornel West, according to the New York Times.

Though he managed to take himself off the ballot in Georgia, North Carolina, Arizona, and Nevada, he’s still on the ballot in Wisconsin. The Wisconsin Supreme Court ruled to keep him on the ballot there, but he has appealed that decision. It’s unclear how the court could render a decision in his favor from a practical standpoint; nearly 100,000 people have already received absentee ballots printed with his name.

A federal judge also ruled that Kennedy must remain on Michigan’s ballot, where the race has narrowed and Harris now holds less than a 1 percentage point lead in FiveThirtyEight’s polling average. 

Other third-party candidates include the Socialism and Liberation Party’s Claudia De la Cruz, the Independent American Party’s Joel Skousen, the Constitution Party’s Randall Terry, and the Socialist Equality Party’s Joseph Kishore. None of them have the support the above four have managed to eke out, however.

Together, these third-party candidates have some potential to cut into both Harris and Trump’s vote margins in states that they need to win. Still, as much as third-party candidates may often appear to siphon away votes from the two major party candidates, the results of the election might not be any different if they were not on the ballot.

“Third-party voters can be quirky and may not be all that gettable by either campaign — perhaps some of them wouldn’t have voted major-party even if those were the only options,” Kondik said.