Arguably the weirdest candidate of the 2024 election is expected to drop out soon.

Following a controversy-filled campaign that included revelations that a worm had eaten part of his brain and that he was responsible for the bear carcass that mysteriously appeared in Central Park in 2014, Robert F. Kennedy Jr., and his running mate Nicole Shanahan, are reportedly planning to suspend their presidential bid. He is considering endorsing former President Donald Trump and reportedly hopeful that he might secure the position of Trump’s health secretary if he wins.

Kennedy was an environmental lawyer known for his work cleaning up the Hudson River with a storied last name who in recent years has become known for spreading conspiracy theories about medicine, including vaccines and anti-depressants. He used the popularity he gained as an anti-vaxxer during the pandemic to briefly challenge President Joe Biden in the Democratic primary before announcing an independent bid for president in October 2023.

He had been seen as a potential spoiler for both candidates, given his connection to the Democratic Kennedy dynasty as well as his embrace of the anti-establishment and anti-vaccine views held by certain segments of the GOP. He was polling around 10 percent nationally for the better part of 2024, and even higher in some swing state polls.

But he struggled to get on the ballot in many states, though his campaign maintains that he has secured enough signatures to do so in all but Kentucky, Mississippi, Rhode Island, and Wyoming. And after Vice President Kamala Harris became the Democratic nominee, he seemed to hold less sway among voters who were turned off by Biden. His poll numbers consequently cratered to under 5 percent.

Despite Kennedy’s flagging national numbers, polling suggests his exit from the race could still help Trump, with whom he’s become decidedly more cozy in recent months. Trump wouldn’t have to win a lot of Kennedy’s potential voters to make a difference in key swing states; if the race is as close as it was in 2020, Trump gaining even a fraction of a percent from Kennedy could make the difference.

Trump probably has the most to gain from Kennedy dropping out. Kennedy has increasingly endeared himself to Republican voters while struggling to get the same support among Democrats and independents. And polls conducted in recent months, including since Biden dropped out of the race, suggest that Trump would pick up more of Kennedy’s supporters. Any margin would likely be small — but potentially significant.

Republicans tend to see Kennedy more favorably than Democrats, and those with favorable views toward him tend to have more favorable opinions of Trump than of Harris, according to a July AP-NORC poll conducted before Biden dropped out.

Several national polls conducted since Harris became the presumptive nominee have also tested a race between Harris, Trump, and Kennedy, as well as a two-way race between Harris and Trump. Trump tends to get a bigger bump than Harris when Kennedy is excluded.

In an August Reuters/Ipsos poll of registered voters, for instance, Harris received 42 percent support, Trump 37 percent, and Kennedy 4 percent, while 15 percent supported another candidate, weren’t sure who they would support, or weren’t sure if they would vote at all. But when voters were pushed to select either Trump or Harris, 49 percent backed Harris and 47 percent Trump — a 10 percentage point boost for Trump.

Trump had a similar edge with Kennedy voters in a July Harvard CAPS/Harris Poll. In a three-way contest, Harris earned 44 percent support, Trump 47 percent, and Kennedy 10 percent. In a head-to-head poll, Harris earned 48 percent and Trump 52 percent.

It may seem like the advantage Trump gains when Kennedy is out of the picture is relatively small. But Biden won in 2020 by exceedingly narrow margins in six key battleground states; in Arizona, it was by less than 11,000 votes. On the margin, Kennedy’s supporters could make a difference, depending on where they’re distributed.

In Arizona, for example, Kennedy is still polling at about 6 percent, according to The Hill’s polling average. Of course, he might not actually win that large a vote share if he decides to stay in the race; third-party candidates tend to poll much better than they actually perform on Election Day, when their supporters are confronted with the reality that their preferred candidate won’t win. But that vote share would have been more than enough to have swung the 2020 results in the other direction.

The same is true in other swing states, where polling suggests a very tight race. An early August New York Times/Siena survey of registered voters in Michigan, Pennsylvania, and Wisconsin found Harris leading Trump 46 percent to 43 percent when respondents were given all third-party candidates to choose from. When asked to pick between just Harris and Trump, the gap tightened to 48 and 46 percent, respectively. Those states are likely to be key, given their high electoral college vote count — and in most scenarios, Harris would need all three to win.

While Kennedy’s supporters may still be able to make an important impact on the margins, their power to drag the Democratic nominee’s polling down seems to have diminished substantially.

Before Harris became the nominee, there was a much larger than usual number of disaffected voters who didn’t like either Biden or Trump and just wanted someone — anyone — as an alternative. A theoretical no-name candidate as an alternative to Biden and Trump got about 10 percent in Ipsos polling conducted earlier this year.

Kennedy provided an alternative for a while. But when Harris stepped up, that undermined his appeal — at least among Democrats.

“There were some wavering Democratic voters who just thought Biden was too old, or they didn’t like him, and Harris is just a more appealing candidate for those kinds of people,” said Kyle Kondik, managing editor of Sabato’s Crystal Ball at the University of Virginia Center for Politics.

Kondik said it’s possible that Biden may have ended up winning back those voters anyway if he had stayed in the race and had a typical post-Democratic National Convention bump.

But at this point, Kondik said, he would not be surprised if the third-party vote share in the election ends up being about 2 percent of the electorate, as it was in 2012 and 2020. Before Harris became the nominee, political analysts were projecting that it would be closer to the nearly 6 percent share third parties got in 2016, which some analysts argued doomed Democratic nominee Hillary Clinton’s candidacy.

“For all the talk about third parties in this election, a combination of the most prominent third-party candidate dropping out, in addition to the increased favorability of the two major party nominees, means that there’s just going to be less of a market for third-party candidates,” he said.

Kennedy could make more of an impact as a surrogate for Trump. He could help the former president with certain demographics, such as young men who listen to prominent personalities such as Joe Rogan, who has praised Kennedy.

But the Trump campaign might also be wary of attaching itself to Kennedy’s brand: If the brain worm and the bear incident weren’t enough, he has been disavowed by members of his own famous family and now peddles conspiracy theories not just about the Covid-19 vaccine, but his father’s killer, 5G cell phone transmission, fraud in the 2004 election, and more.

“The Democratic refrain against Trump and [his running mate JD] Vance is that they’re ‘weird,’” Kondik said. “Kennedy doesn’t make them less weird.”