Robert F. Kennedy Jr. suspended his independent presidential campaign and endorsed former President Donald Trump at a rally in Arizona on Friday. Trump gave him a dramatic welcome, complete with pyrotechnics and the walk-on song “My Hero.”

Democrats, who spent more than a year and millions of dollars arguing the presence of the conspiratorial scion of one of the American establishment’s most prominent families was a direct threat to their electoral hopes, are now insisting the Trump campaign’s song won’t turn out to be prophetic.

But with Vice President Kamala Harris at the top of the ticket and Kennedy’s numbers cratering with Democratic-leaning voters, it’s not clear their efforts won’t end up helping Trump in an election likely to come down to a few thousand votes in just a handful of states.

On Monday, Kennedy told right-wing radio host Glenn Beck that his internal polling showed a large majority of his supporters would vote for Trump if he were not in the race. Kennedy dropped out in order to avoid spoiling Trump’s bid against Harris, he told Beck.

“The likelihood was that my presence in the race would get Vice President Harris elected,” Kennedy said.

There is evidence in public national polling to back up Kennedy’s claims. If forced to choose between Harris and Trump, 48% of Kennedy voters would back Trump, compared with 23% for Harris and 29% who “don’t know,” according to a New York Times/Siena College poll conducted in late July. The same poll found Harris trailing Trump in a head-to-head contest but tied when Kennedy and three other third-party candidates were figured into the race.

Democratic operatives, however, insisted Kennedy’s effect would end up being minimal.

“Here’s what RFK Jr.’s endorsement of Donald Trump would change: nothing,” the Democratic National Committee wrote in a memo Friday. “Once around 15%, RFK Jr.’s support has been in free fall ― now under 5% ― and he’s not positioned to deliver any electoral benefit to Trump.”

Democrats, of course, did not always treat Kennedy like he was going to have a marginal effect. The DNC set up an opposition research and media unit to combat all third-party candidates but focused a big chunk of its firepower on Kennedy.

That outfit, and other Democratic initiatives, likely played a behind-the-scenes role in the steady stream of embarrassing stories about Kennedy, from the worm he says ate part of his brain to the tale of him leaving a dead bear cub in Manhattan’s Central Park posed to make it look like a hit-and-run biking accident.

Meanwhile, a separate Democratic super PAC contested Kennedy’s ballot access in critical states across the country, seizing on Kennedy’s claims that his main residence is in New York rather than California. (Kennedy’s running mate, Nicole Shanahan, also lives in California. And thanks to an obscure provision of the U.S. Constitution, having two candidates from California would have made it difficult for them to both run without forfeiting California’s electoral votes.)

That effort to boot Kennedy from the ballot was on track to be especially fruitful in Pennsylvania, the state most likely to provide the 270th electoral vote for either candidate to win the presidency.

Last Tuesday, Kennedy appeared late for a hearing about his ballot eligibility in the Keystone State, eliciting a rebuke from the judge and making his disqualification likely. (On Monday, having suspended his campaign, Kennedy withdrew his application for ballot access.)

Though Trump had denigrated Kennedy as a “radical left” proponent of “ridiculous Open Borders and the Green New Scam,” the one-time environmental activist’s appeal to conservatives has long been apparent. He railed against the “deep state” and the dangers of the COVID-19 vaccine, opposed additional U.S. aid to Ukraine, and took conservative positions on border security and gun control.

Joe Zepecki, a Democratic strategist in Wisconsin, argued Kennedy’s numbers were due to collapse, with or without a nudge from national Democrats, shortly after Harris replaced President Joe Biden as the Democratic nominee in late July. That’s because so much of Kennedy’s appeal was with the voters known as the “double haters.” Those were the disaffected, often less politically active voters fed up with both Trump and Biden, and desperately seeking an alternative.

Harris’ replacement of Biden allowed many of Kennedy’s more liberal supporters ― young people, Latinos and Black voters ― to return to the Democratic fold, according to Zepecki.

“Once that underlying premise wasn’t the choice, what the hell exactly was the rationale behind the Kennedy campaign? There was none,” Zepecki said. “That’s why these numbers were going south.”

Ian Russell, a former political director for the Democratic Congressional Campaign Committee, had a similar analysis of the “double haters” coalition breaking apart.

“I just don’t think him being on the ballot was going to have much of an effect one way or the other,” said Russell, who advises federal candidates in battleground states and districts.

“There’s an argument to be made that it would be marginally better to have him on the ticket,” he added. “But I don’t think it’s as simple as taking the 4% in his camp and moving them to Trump’s share of the vote.”

But considering that the 2016 and 2020 elections were decided by 80,000 and 44,000 votes, respectively, the Trump campaign is taking any help it can get. In a memo Friday, Trump pollster Tony Fabrizio wrote that the net benefit of Kennedy leaving the race would propel Trump to surpass Biden’s 2020 margins in states like Arizona and Georgia.

“This is good news for President Trump and his campaign ― plain and simple,” Fabrizio wrote.

With Kennedy now pulling primarily from anti-establishment conservatives rather than disaffected Democrats, would it have been better for Harris if Democrats had decided not to work quite as hard to destroy him?

“I don’t think so. We’ll never really know,” said Matt Bennett, executive vice president of the moderate Democratic group Third Way, which previously teamed up with the liberal group MoveOn to combat a potential third-party candidate backed by No Labels. “The numbers we’re talking about are really, really small compared to the broader electorate, and it’s very hard to parse them.”

Even public polling showed Kennedy’s supporters had less-traditional voting patterns and spottier records of participation altogether. More than one-third (34%) of those supporting him in the Times/Siena poll in late July said they had not voted in the 2020 presidential race.

Brody Lineaweaver, a college student in New York City who had been doing student organizing for the campaign since April, told HuffPost he feels “betrayed” by Kennedy’s decision. Lineaweaver, a self-described progressive who got involved with Kennedy’s campaign to challenge the two-party system, estimates that a large majority of Kennedy’s support came from anti-establishment voters like him and that those voters are more likely to stay home now rather than vote for Trump.

A smaller category of “Kennedy loyalists” who are more attached to his anti-vaccine message “seems to be following Kennedy more into Trump kingdom,” Lineaweaver said. For his part, Lineaweaver, who is registered to vote in Colorado, where he grew up and his parents live, plans to write in left-wing author Marianne Williamson or Sen. Bernie Sanders (I-Vt.).

In fact, some Democrats see Kennedy potentially costing Trump votes in the center of the political spectrum with his conspiracy theories, anti-vaccine worldview and history of outlandish and distasteful behavior.

“The really important thing here is that Kennedy probably doesn’t bring a whole lot of voters with him, but by adding his voice to the Trump campaign … it really hurts Trump’s ability to attract those voters who are still in play,” he said. “Bringing in Bobby Kennedy at this point really can’t help with ‘normie’ voters who are just hoping they can trust Trump not to be crazy.”

Other Democrats maintain that their strategy for attacking Kennedy could never be based on where he stood in the polls, given how much that changed day to day.

“We always thought that polling would fluctuate throughout, and our two goals were to educate voters and make sure that he was playing by the rules,” said Matt Corridoni, a spokesperson for the Democratic National Committee’s anti-third party initiative. “We always knew this would be a close race, and we could not leave him unchecked.”

Kennedy’s endorsement of Trump speaks to both Kennedy’s and Trump’s weakness as candidates, according to Corridoni.

“This is not a decision that either campaign is making from a place of strength,” Corridoni said. “Kennedy waited until when he was at his absolute lowest and did really not have folks to bring with him, and Trump is so desperate right now for any type of bump that he’s willing to take on everything that comes with RFK Jr.”