Independent presidential candidate Robert F. Kennedy Jr. abandoned his campaign on Friday and endorsed Republican Donald Trump, ending a presidential bid that he began as a Democrat, trading on one of the most famous names in American politics.

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 November 5 election.

Kennedy said he met with Trump and his aides several times and discovered 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 stated at a news conference.

Kennedy announced he would remove his name from the ballot in 10 battleground states likely to determine the election's outcome 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 initially 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 percent 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.

His sister, Kerry Kennedy, said on Friday that his decision to endorse Trump betrayed the family's values. "It is a sad ending to a sad story," she said on social media.

For a time, both the Biden and Trump campaigns showed signs of concern that Kennedy could draw enough support to change the election's outcome.

But as the race rapidly evolved 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, aged 70, waned.

An Ipsos poll early this month showed his national support had fallen to 4 percent, a small figure, but one that could still be meaningful in a tight race like the current Trump-Harris matchup.