RFK Jr just endorsed Trump. Will it matter in November?

His decision to throw his support behind Trump will vindicate those allegations in the minds of Kennedy critics.

“I think some of his voters will vote for Trump, and there are others who won’t be satisfied with either candidate and who just won’t vote,” said Melissa Smith, author of Third Parties, Outsiders, and Renegades: Modern Challenges to the Two-Party System in Presidential Elections.

But Mr Kennedy’s campaign, struggling for cash, might have had more impact on the race if he had stayed in, or dropped out at the last minute.

With more than two months to go until election day, Ms Smith predicted that his run would be a “blip in history”, which could quickly become old news in an election contest that has already thrown up lots of surprises.

For now, however, Trump appears better placed to capture more of what’s left of Mr Kennedy’s support.

The Trump campaign released a memo from its pollster Tony Fabrizio, stating that Republicans stand to gain.

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

But his endorsement also poses some risk for Trump, as Democrats seek to define the Republican ticket as “weird” – by which they mean outside the mainstream of American politics.

Mr Kennedy, with his fringe anti-vaccination views, could end up providing more material for such attacks.

Outside this week’s Democratic National Convention, a tongue-in-cheek newspaper stating that it was funded by his campaign boasted the headline “Kennedy is weird”.

Chock-full of anti-vaccine messages and references to conspiracy theories, its underlying message was that “weird” is good.

The Harris campaign, meanwhile, did not directly refer to RFK Jr in a statement responding to the news on Friday.

“For any American out there who is tired of Donald Trump looking for a new way forward, ours is a campaign for you,” said Harris campaign chair Jen O’Malley Dillon.