Ending months of speculation, Vice President Joseph R. Biden announced Wednesday that he won’t seek the Democratic nomination for president in 2016, removing a potential threat to front-runner Hillary Rodham Clinton even as he scolded her for partisanship.
Speaking with President Obama and his wife Jill Biden in the White House Rose Garden, Mr. Biden said his family’s grieving since the death of his son Beau in May had pushed him too far into the 2016 political calendar.
“Unfortunately, I believe we’re out of time — the time necessary to mount a winning campaign for the nomination,” the vice president said.
But as he bowed out of contention, Mr. Biden also took a swipe at Mrs. Clinton, who said in a debate last week that Republicans were her “enemies.”
“We have to end the divisive partisan politics that is ripping this country apart,” Mr. Biden said, without mentioning Mrs. Clinton by name. “It’s mean-spirited and it’s petty. I don’t think we should look at Republicans as our enemy. They’re opposition, they’re not our enemies. Compromise is not a dirty word. Four more years of this kind of pitched battle may be more than this country can take.”
In a statement, Mrs. Clinton made no reference to the vice president’s rebuke, calling Mr. Biden “a good man and a great vice president.”
“Like millions of others, I admire his devotion to family, his grace in grief, his grit and determination on behalf of the middle class, and his unyielding faith in America’s promise,” she said. “Joe has been by President Obama’s side for every pivotal decision. It’s a record to be proud of, defend, and build on. And I am confident that history isn’t finished with Joe Biden.”
Mr. Biden, 72, has run for president twice before with poor results, in 2008 and 1988. He has been debating another bid in earnest since his son died in May from brain cancer.
His candidacy would have posed a huge challenge for Mrs. Clinton, a former Senate colleague and the former secretary of State who has been struggling to emerge from scandals ranging from Benghazi to her private email server.
Calls from Clinton allies for Mr. Biden to stay out of the race had increased since Mrs. Clinton gave what they viewed as a strong performance in the first Democratic presidential debate last week.
Democratic National Committee Chairwoman Debbie Wasserman Schultz thanked Mr. Biden for “giving thoughtful consideration” to seeking the nomination.
“While Vice President Biden will not be a candidate next year, his unwavering commitment to America’s working families is a legacy each of our candidates will proudly carry forward,” the Florida Democrat said in a statement.
Republican National Committee Chairman Chairman Reince Priebus said Mr. Biden’s decision is “a major blow for Democrats, who now will almost certainly be saddled with their unpopular and scandal plagued front-runner Hillary Clinton.”
“Vice President Biden was the most formidable general election candidate the Democrat Party could have fielded, and his decision not to challenge Hillary Clinton greatly improves our chances of taking back the White House,” Mr. Priebus said in a statement.
Recent polling doesn’t bear out Mr. Priebus’ claim. A compilation of seven major polls showed that if Mr. Biden had entered the Democratic primary, he would have received 17 percent support, a distant third behind Sen. Bernard Sanders of Vermont (26 percent) and Mrs. Clinton at 47 percent. An NBC/Wall Street Journal national poll this week put Mrs. Clinton at 49 percent, Mr. Sanders at 29 percent and Mr. Biden at only 15 percent.
A WBUR poll this week in New Hampshire, which will hold the first-in-the-nation primary in February, showed Mrs. Clinton receiving 38 percent support, followed by Mr. Sanders at 34 percent and Mr. Biden at 9 percent, although the vice president had no campaign staff or fundraising operation.
Mr. Biden’s decision leaves Mr. Sanders as the only serious challenger to Mrs. Clinton’s second bid to capture the Democratic nomination. “Joe Biden, a good friend, has made the decision that he feels is best for himself, his family and the country,” the Vermont independent said in a statement.
In the president’s inner circle, reaction to Mr. Biden’s decision was “relief with a tinge of ‘this dark cloud has finally passed on by,’” said Jim Manley, a Democratic strategist with close ties to the White House.
“The back-and-forth was driving some folks nuts over the last couple of weeks,” he said of the president’s aides, who were being confronted daily with questions about the political intrigue while trying not to take sides publicly.
The president didn’t comment during the Rose Garden announcement, nor did he refer to Mr. Biden later at his only public appearance of the day, in Charleston, West Virginia.
Mr. Obama hadn’t tipped his hand publicly about a preference between Mrs. Clinton and Mr. Biden, although he appeared to be encouraging the vice president to run, saying he wanted to give him “space” to make a decision and calling him the most important adviser of his presidency.
But the president also gave Mrs. Clinton a warm send-off when she resigned as secretary of State in January 2013, sitting with her for an interview on CBS’ “60 Minutes” and calling her “a strong friend” and “one of the finest secretary of states we’ve had.”
Speaking of Mr. Obama’s apparent encouragement of Mr. Biden’s candidacy, one Democratic insider said, “I found the whole thing very confusing.”
After announcing that he won’t be a candidate, Mr. Biden embarked on a would-be stump speech in the Rose Garden, urging the Democratic presidential candidates to run on Mr. Obama’s record on education, foreign policy and middle-class economics.
“While I will not be a candidate, I will not be silent,” Mr. Biden said. “We need to level the playing field for the American people.”
He appeared to take another shot at Mrs. Clinton for distancing herself from some of Mr. Obama’s policies, such as the Trans-Pacific Partnership free-trade deal and Syria’s civil war.
“Democrats should not only defend this record and protect this record, they should run on the record,” Mr. Biden said.
The vice president, obviously thinking of his late son, also called on the nation to wage “a moon shot” campaign to cure cancer.
“Beau was our inspiration,” he said, adding that the process of grieving with his family conflicted with the work necessary for gearing up a nationwide political campaign.
“The [grieving] process doesn’t respect or much care about things like filing deadlines or debates or primaries and caucuses,” Mr. Biden said. “My family has suffered loss.”
Days before his death, Beau Biden urged his father to run for president. After Beau’s death, Mr. Biden said he would make a decision by the end of the summer, as he spent much time grieving with his daughter-in-law and his young grandchildren in Delaware.
By mid-September, however, the vice president was still giving no firm indications about his plans, and the deadlines for filing as a presidential candidate in various states were fast approaching. Supporters and loyalists formed a “Draft Biden” Super PAC that aired one advertisement on his behalf in early October. Mr. Biden’s aides quickly asked that the ad be pulled.
Will Pierce, executive director of Draft Biden, said the group was grateful for “the gigantic outpouring of support from hundreds of thousands of Americans around the country in our effort to encourage the vice president to run.”
In recent days, some observers and aides had seen signs that Mr. Biden intended to run. The speculation intensified as Mrs. Clinton prepared to testify before a House select committee investigating the Benghazi attacks, an issue which some Democrats fear will leave her as a weakened candidate.
At a public forum on Monday, Mr. Biden said he had advised the president in 2011 to approve the special-operations raid that killed Osama bin Laden in Pakistan. That version of the story differed from his past statements about the high-level deliberations, in which he’d said he had been unsure what the president should do.
A freshman Democratic House lawmaker, Rep. Brendan Boyle of Pennsylvania, raised more speculation on Monday when he said on Twitter that a good source told him Mr. Biden would enter the race.
Mr. Biden’s decision caps a career in Washington that began in 1972, when he was elected to the Senate from Delaware.
He went on to be re-elected to the Senate six times before becoming vice president in 2009.
Mr. Biden lost another child decades ago. His 13-month-old daughter, Naomi, and his first wife, Neilia, died in a car accident in December 1972, just weeks after he was elected to his first term in the Senate.