President Joe Biden endorsed Vice President Kamala Harris to replace him as the Democratic nominee when he dropped his reelection bid against former President Donald Trump on Sunday.
"My very first decision as the party nominee in 2020 was to pick Kamala Harris as my Vice President. And it's been the best decision I've made," Biden said on social media.
Biden also said he wanted to "offer my full support and endorsement for Kamala to be the nominee of our party this year."
He added: "Democrats — it's time to come together and beat Trump. Let's do this."
The move came in response to mounting pressure on the 81-year-old president to quit his campaign following his disastrous debate against Trump on June 27.
Biden's admittedly poor performance, which he blamed on a bad cold, raised widespread concerns about his mental fitness and ability to win a second term.
In a statement, Harris called Biden's decision to quit his campaign a "selfless and patriotic act" that she said showed "what he has done throughout his life of service: putting the American people and our country above everything else."
Harris also vowed to "earn and win" the Democratic nomination for president, which would make her the first Black woman to head a White House ticket.
The Democratic National Convention is scheduled for Aug. 19-22 in Chicago.
Former President Donald Trump, who Republicans nominated last week in Milwaukee, told CNN minutes after Biden dropped out that he thought Harris would be easier to beat than Biden would have been.