Strategists said it was unclear whether Kennedy's endorsement would help Trump, who is locked in a tight contest with Democratic Vice President Kamala Harris ahead of the Nov. 5 election.
Kennedy said he met with Trump and his aides several times and learned they agreed on issues like border security, free speech and ending wars.
"There are still many issues and approaches on which we continue to have very serious differences. But we are aligned on other key issues," he said at a news conference.
Kennedy said he would remove his name from the ballot in 10 battleground states likely to determine the outcome of the election and remain as a candidate in other states.
An environmental lawyer, anti-vaccine activist and son and nephew of two titans of Democratic politics who were assassinated during the turbulent 1960s, Kennedy entered the race in April 2023 as a challenger to President Joe Biden for the Democratic nomination.
With voters at the time turned off by both the aging Biden and the legally embattled Trump, interest in Kennedy soared. He shifted his plans and decided to run as an independent, and a November 2023 Reuters/Ipsos poll showed Kennedy drawing the support of 20% of Americans in a three-way race with Biden and Trump.
He ran a high-profile advertisement during the February 2024 Super Bowl that invoked his father, U.S. Senator Robert F. Kennedy, and uncle, President John F. Kennedy, and drew outrage from much of his high-profile family.
For a time, both the Biden and Trump campaigns showed signs they were worried that Kennedy could draw enough support to change the election outcome.
But as the race changed quickly in the last two months -- with Trump surviving an assassination attempt and the 81-year-old Biden bowing to pressure from his own party and passing the campaign torch to Harris -- voter interest in Kennedy, 70, waned.
An Ipsos poll early this month showed his national support had fallen to 4%, a tiny number, but one that could still be meaningful in a tight race such as the current Trump-Harris matchup.
Trump celebrated Kennedy's endorsement at a campaign stop in Las Vegas. "I want to thank Bobby. That was very nice," Trump said. "He's a great guy, respected by everybody."
Democrats shrugged off the announcement.
"Donald Trump isn’t earning an endorsement that’s going to help build support, he’s inheriting the baggage of a failed fringe candidate. Good riddance," Democratic National Committee senior adviser Mary Beth Cahill said in a statement.
Drexel University political science professor William Rosenberg said the move was unlikely to have an impact on the race, given Kennedy's low poll numbers. "If he would have done this three months ago, maybe it would have had a different kind of impact," he said.
Trump pollster Tony Fabrizio argued that more of Kennedy's supporters would back Trump than Harris in battleground states. "This is good news for President Trump and his campaign," he wrote in a memo.
In exchange for endorsing Trump, Kennedy was hoping for a job in a potential Trump administration, a super PAC supporting Kennedy told Reuters on Wednesday.
Kennedy painted himself as a political outsider. He told Reuters in an interview in March that if elected president he would repeal many provisions of Biden's signature Inflation Reduction Act and would seek to close down the southern border to immigrants entering the U.S. illegally. He also offered staunch support for Israel.
Trump mega-donor Timothy Mellon, an 82-year-old banking heir, has given millions of dollars this election cycle to support Kennedy, and $75 million to support of Trump, according to Federal Election Commission filings through July 31.
In a video of a phone call posted online last month, Trump suggested to Kennedy that the independent candidate could do something to support the Trump campaign.
BEAR, BRAIN WORMS
Kennedy said this month in a video posted online that he dumped a dead bear in New York City's Central Park a decade ago and staged it to look like a bike had hit it. He proclaimed he had "so many skeletons in my closet" after a former family babysitter accused him of sexual assault. He denied that a picture of him posing with the barbecued carcass of a large animal belonged to a canine.
And then there was the brain worm. Kennedy's campaign confirmed that he had a parasite in his brain more than a decade ago, but has since fully recovered, drawing widespread ridicule.
