Biden, who had been pondering a run since August, appeared in the White House Rose Garden with his wife Jill and President Barack Obama to say the window for mounting a successful campaign had closed.
“While I will not be a candidate, I will not be silent,” Biden told reporters. “I intend to speak out clearly and forcefully to influence as much as I can where we stand as a party and where we need to go as a nation,” Biden said.
Biden, 72, had been wrestling with his own doubts about whether he and his family were ready for a grueling campaign while still mourning his son Beau, who died of brain cancer in May. His son had urged him to run.
Clinton’s slipping poll numbers amid the controversy over her use of a private email server while secretary of state had cracked open a door to a late bid by the affable Biden, leading to calls from his supporters to seek the presidency.
But what was widely hailed as a command performance by Clinton in the Oct. 13 Democratic debate turned the tide back in her favor and quieted talk that she was vulnerable in her quest for her party’s nomination for the November 2016 election.
Biden’s decision was a huge boost for Clinton, whose prime challenger now is U.S. Senator Bernie Sanders of Vermont. The democratic socialist has galvanized the party’s left-wing but has yet to prove he can broaden his appeal.
“It’s an easier path for Hillary Clinton now,” said Democratic strategist Bud Jackson. “Most polls reflect that without Biden in the race, it’s more beneficial to her.”
Clinton’s support among Democrats surged by 10 percentage points after the October debate, a Reuters/Ipsos poll showed. She had the backing of about 52 percent of poll participants, followed by Sanders at 27 percent. Biden’s support, at 13 percent, was down 6 percentage points.
Jumping into the race so late would have presented a huge challenge to Biden, who would have had to quickly build a fundraising network and campaign structure ahead of the first nominating contest in Iowa on Feb. 1.
“Unfortunately, I believe we’re out of time, the time necessary to mount a winning campaign for the nomination,” Biden said in the Rose Garden. “The process doesn’t respect or much care about filing deadlines or debate or primaries and caucuses. But I also know I couldn’t do this if the family isn’t ready.”
Biden is popular with white, working-class voters, and he could still play a major role in the election if he chooses to endorse a Democratic candidate.
Also in the running for the Democratic nomination are former Maryland Governor Martin O’Malley and former Rhode Island Governor Lincoln Chafee.
Biden ran for president in 1988 and 2008, both times dropping out early in the race. He was a U.S. senator from Delaware for more than three decades.
He has been prominent for a vice president, with broad involvement in many of Obama’s foreign affairs decisions, such as the withdrawal from Iraq and his Afghanistan strategy.
Biden once boasted that he had “met virtually every major leader in the world.”
He became something of a secret weapon for the White House on Capitol Hill, stepping in to negotiate tricky fiscal deals with Republican lawmakers.
Biden, who is Roman Catholic, won praise from human rights groups for saying in May 2012 that he was “absolutely comfortable” with same-sex marriage. Many observers credited his comments for pushing Obama to announce his support too.
In Biden’s long Senate career, he served as chairman of the Foreign Relations Committee. He also pushed for the Violence Against Women Act, which toughened penalties for sex offenders and created protections for victims.