Robert F. Kennedy Jr. is poised to be the most formidable independent presidential candidate in more than two decades.

And already, operatives in both parties are moving to head off the impact.

A combination of his famous name and widespread voter dissatisfaction with both likely major party nominees puts him in position to earn the largest share of the vote for an independent candidate since Ross Perot drew nearly 19 percent in the 1992 election.

Given the recency of Kennedy’s flirtation with an independent bid, there isn’t a lot of polling testing a three-way race with President Joe Biden and former President Donald Trump.

But in recent weeks, two polls have found Kennedy at 14 percent when included as a third option with Biden and Trump.

In a tight race in which every small advantage matters, both parties are anxious about how Kennedy could draw from their coalitions. Allies of President Biden have called his independent candidacy “dangerous.” And the Republican National Committee, conscious of how he has drawn on the anti-vaccine crowd among its base, is already highlighting Kennedy’s liberal policy positions, eager to stamp out any support he has on the right.

Kennedy’s support so far is coming roughly evenly from Biden and former President Donald Trump. But third-party candidacies can be unpredictable, and Kennedy’s anti-vaccination stance gives him more room to draw from Republicans than Democrats.

Democrats aren’t excited by Biden’s campaign, and many say they wish he wasn’t running again. But Kennedy likely isn’t the right candidate to pull them away. And in the course of the campaign, it’s probably more likely Kennedy’s independent bid would ultimately hurt Trump. Kennedy could play a major role in the 2024 race

It’s not clear whether the current polling represents Kennedy’s floor, ceiling or somewhere in between. But he could have the financial resources to mount a credible campaign. In addition to the campaign itself, Kennedy has the backing of a super PAC, American Values 2024, that is funded mostly by conservative donor Timothy Mellon and billionaire Gavin de Becker. That PAC already had $9.8 million in the bank as of the end of June. That’s still far less than Biden and Trump will have to spend, but Kennedy’s wealthy donors could do more to close the gap in the coming months.

Starting at 14 percent would put Kennedy just shy of the 15 percent average polling threshold used in previous elections by the Commission on Presidential Debates to determine whether independents can qualify for debates. No third-party candidate has participated in a debate since Perot in 1992 — and that’s also the last time a single independent candidate reached double-digits in the national popular vote.

Then again, there might not be any debates next year. The RNC has vowed that its nominee won’t participate in any debates run by the nonpartisan commission, which could leave the two parties haggling over new rules — including for third-party contenders — if the candidates want to debate at all.

Third-party voting tends to increase when the two major-party candidates are unpopular. In 2016, both Trump and Hillary Clinton had majorities of the electorate viewing them unfavorably, and nearly 6 percent of voters chose a third-party candidate.

[see graphic of polling data]

That wasn’t the case in 2020, when voters were happier with Trump and Biden, and third-party voting dropped to fewer than 2 percent. But Trump and Biden are now collectively less popular than Trump and Clinton were in 2016, so third-party voting could spike again next year. Biden’s RFK Jr. challenge: Democrats aren’t loyal to him

Kennedy’s greatest opening with Democratic-leaning voters is their lack of enthusiasm for Biden’s reelection campaign. A significant number of Democrats and Biden 2020 voters don’t think the president should be seeking another term and say they are open to supporting other candidates.

In a poll released last week by Republican firm Echelon Insights, Kennedy drew 16 percent of voters who said they voted for Biden in 2020, compared to a slightly smaller number, 10 percent, of Trump voters. Overall, Kennedy was backed by 13 percent of Democrats, 9 percent of Republicans and 23 percent of independents on the ballot test.

There’s also other data that suggests Biden supporters might be easier to peel off, particularly if a third-party candidate like Kennedy actually became viable. Last month’s NBC News poll didn’t ask about Kennedy specifically, but it showed a tied race between Biden and Trump in which Trump’s supporters are far more enthusiastic about their candidate.

Only 38 percent of those who picked Biden said their choice was about supporting him; a majority, 58 percent, said they were voting against Trump more than for Biden.

The numbers were reversed among Trump voters: 56 percent said they were voting for Trump, while 36 percent were voting against Biden. RFK Jr. still probably helps Biden in the end

Despite Biden’s weaknesses, Kennedy’s independent candidacy could end up being the spoiler to help the president secure a second term.

Polls consistently show Kennedy is more popular with Republicans than Democrats, a phenomenon that emerged during Kennedy’s ill-fated primary against Biden, as the campaign put the activist’s longtime skepticism about vaccines in the spotlight, and Kennedy made a host of appearances on Fox News.

Those positions are a poor match with Democratic voters, which essentially doomed any chance Kennedy had to win the nomination. A POLITICO | Morning Consult poll last month found widespread Democratic support for vaccinations of all kinds, with opposition coming significantly more from Republicans and independents. And a general election spotlight is almost certain to bring more attention to the issue.

And while the Echelon Insights poll suggested Kennedy could take more from Biden, a Reuters/Ipsos survey released last week was basically a mirror image, with Kennedy drawing 9 percent of self-identified Democrats, 13 percent of Republicans and 24 percent of independents.

That’s not a significant difference, but Kennedy might have more room to grow among Republicans: 59 percent of Republicans said they have a favorable opinion of Kennedy in the Reuters/Ipsos poll, compared to 40 percent of Democrats.

So while Democrats may not be enthusiastic about Biden, Kennedy might struggle to pull them away — especially the large numbers of those who say they are worried about Trump returning to the White House. Kennedy’s super PAC has its own polling showing the son of the former senator and attorney general drawing slightly more votes from Trump than Biden, though the differences were well within the margin of error.

There are also signs Kennedy sees an opportunity among Republican voters to power his independent bid. He is scheduled to appear in Las Vegas later this month hosted by the Conservative Political Action Conference at which right-wing figures like presidential candidate Vivek Ramaswamy and Arizona Senate hopeful Kari Lake are also on the bill.