I’ll say it again and again: The 2024 presidential election will be a very close race.

Head-to-head national polling averages currently have President Joe Biden and former president Donald Trump – the two major parties’ presumptive nominees – in a statistical dead heat. Some averages show Trump with a slight lead, but one that lies within most polls’ margins of error.

While the polls will no doubt seesaw back and forth over the next seven months, don’t get fooled by the noise. Because of the Electoral College and America’s growing political polarization, the outcome of US elections is determined not by the national popular vote but by the states – and, increasingly, by just tens of thousands of voters in a handful of swing states.

Trump carried most of these in 2016, and Biden flipped most in 2020. The former was decided by about 78,000 votes in Michigan, Pennsylvania, and Wisconsin. The latter, by about 44,000 votes in Wisconsin, Arizona, and Georgia. Something similar will happen this upcoming November, with the winner virtually guaranteed to have a narrow path to the White House.

Polls consistently show that most Americans dislike both Biden and Trump and want neither to lead the nation again. The unprecedented unpopularity of both nominees makes 2024 the most favorable environment in a generation for third-party candidates, three of whom are currently in the running: Robert F. Kennedy Jr., Cornel West, and Jill Stein.

But could they have an impact on the election’s outcome? And if so, to whose benefit?

Polls show third parties hurt Biden more on net

First, let’s dispense with the obvious. Third-party candidates have no chance of winning any states in 2024. Not even Ross Perot’s 19% of the nationwide popular vote in 1992 was enough to win him more than a few counties.

But third parties don’t need to win any states or even significant numbers of votes to influence the 2024 result. Even single-digit vote shares could be enough to shift margins in the closely contested swing states that will decide the election, as they have in several recent contests. Indeed, third-party candidates picked up more votes than the eventual winner’s margin of victory in 75% of swing states in the 2016 and 2020 presidential elections. Insofar as the 2024 race is close, it won’t take many third-party votes in the right places to spoil it.

The strongest third-party candidate in decades courtesy of his family’s name recognition, independent RFK Jr. is easily the best-performing of the three, currently registering 10.4% in the RealClearPolitics five-way national polling average. The far-left West and Stein are each polling at around 1.9% on average. In the six swing states that matter most (Arizona, Georgia, Michigan, Nevada, Pennsylvania, and Wisconsin), RFK Jr. is polling at 8.8% on average, while West is polling at 1.8% and Stein at 1.5%.

Whereas polls last year showed RFK Jr. siphoning more votes from Trump than Biden in a three-way race, more recent polling finds him drawing roughly equal support from both candidates, with some even showing him hurting Biden slightly more. But the margins are small, and the data is far from conclusive.

On the one hand, RFK Jr. bears the most famous name in Democratic politics and is the scion of legendary Democratic leaders such as former President John F. Kennedy and former Massachusetts Sen. Ted Kennedy. An environmental lawyer and activist, Kennedy himself was a lifelong Democrat and competed in the Democratic primary until last October, so it’s not a stretch to assume that most voters who recognize and react favorably to him are likely to be … Democrats. Crucially, Democrats (especially young, progressive, and minority voters) report being less enthusiastic about Biden as their nominee than Republicans are about Trump, suggesting the former would be more open to voting for an alternative candidate such as RFK Jr.

On the other hand, the No. 1 reason to think RFK Jr. could hurt Trump more than Biden is that Republicans and Republican-leaning independents like him much more than Democrats and Democratic-leaning independents do. While the exact numbers vary from poll to poll, Kennedy’s average net favorability is positive among Republicans and negative among Democrats. This trend has grown over time as voters have gotten to know RFK Jr. better and realized his anti-establishment views put him closer to the Republican base than the Democratic one. To name just a few, he is a vocal anti-vaxxer, opposes gun control and Ukraine aid, and has a knack for conspiratorial thinking. All these positions are right-wing coded, appealing more to the reactionary populism of Joe Rogan, Tucker Carlson, and Alex Jones than the suburban, college-educated liberals who make up the base of the Democratic Party.

Whether he hurts Biden or Trump more will remain an open question for months to come, but what is clear is that Kennedy appeals to disaffected voters on both sides of the aisle who are skeptical of elites and have little commitment to either major-party candidate. It’s also possible that he ends up taking about even support from both of them in the “tipping point” states, in which case he wouldn’t ultimately matter much at all.

By contrast, the far-left campaigns of West and Stein pose a problem for Biden, despite their much smaller vote shares. Biden’s margin against Trump in national and swing state polls is consistently worse with these candidates included than without. Neither West nor Stein will attract any voters who would otherwise support Trump; their appeal is limited almost exclusively to progressives (especially young and non-white Americans) who would either vote for the president or stay home if they weren’t on the ballot. While votes they gain from those who’d otherwise not vote won’t sway the election, siphoning votes from Biden in swing states while taking none from Trump certainly could.

On balance, then, third parties’ continued presence in the race is a bigger threat to Biden and one of the reasons why I believe Trump is slightly favored to win the race at the moment.

Ballot access remains the key obstacle

Polling aside, third-party candidates will have no impact in November if they can’t qualify for the presidential ballot in key swing states.

Gathering the hundreds of thousands of signatures necessary to appear on all 50 state ballots costs millions – possibly tens of millions – of dollars and is usually an impossibly tall order for independent candidates running ballot-qualification campaigns from scratch on shoestring budgets. That’s why the sole independent candidate in the 2020 election qualified for the ballot in only 13 states, none of them swing states. Third-party candidates running under an established minor-party label – such as the Green Party or Libertarian Party – have an easier time with ballot qualification, as most states have lower ballot qualification standards for established minor parties than for true independents.

RFK Jr. has made significant progress on this front in recent weeks, having reportedly amassed enough signatures to qualify for the ballot in Arizona, Georgia, Nevada, Michigan, and New Hampshire, as well as in several non-swing states. The financial backing of his newly picked running mate, wealthy Bay Area lawyer, entrepreneur, and philanthropist Nicole Shanahan, makes it all the more likely that he will qualify for more key state ballots. Should Kennedy manage to secure the nomination of the Libertarian Party at the party’s convention in May, which seems reasonably likely, he would have a straightforward path to appearing on nearly all of them.

The story for the far-left candidates is more mixed. Stein will appear on the ballot in most states by virtue of running under the Green Party label. West, on the other hand, has neither the organizational apparatus nor the funding to mount a nationwide qualification drive. He seems to have secured a place on the ballot only in Utah and South Carolina – two non-swing states – thus far; the considerable challenges he faces to qualify in swing states could render his campaign dead in the water by the end of the summer.

The deadlines for ballot access run from June to August. This means that we are still months away from knowing which states third-party candidates will qualify in – and how exactly they might shake up the 2024 race.

What we do know is that they could.