Michael R. Bloomberg announced on Sunday that he would run for president in 2020, bringing his enormous wealth and eclectic political biography into the tumultuous Democratic primary and seeking to win over skeptical liberal voters by presenting himself as a multibillion-dollar threat to President Trump.
Mr. Bloomberg, a former Republican who has expressed reservations about his adopted party’s leftward drift, said in a statement that he would offer a pragmatic option to voters in a campaign to unseat a president who “represents an existential threat to our country and our values.”
“Defeating Donald Trump — and rebuilding America — is the most urgent and important fight of our lives. And I’m going all in,” Mr. Bloomberg said. “I offer myself as a doer and a problem solver — not a talker. And someone who is ready to take on the tough fights — and win.”
Mr. Bloomberg’s late entry into the race has already roiled an unsettled Democratic primary field. He has startled rival campaigns in recent days by reserving almost $35 million in airtime for television commercials outlining his biography and political agenda, a figure that dwarfs other campaigns’ advertising budgets. On a website that went live on Sunday, Mr. Bloomberg embraced his status as a surprise contender, branding himself as “a new choice for Democrats.”
Mr. Bloomberg, 77, faces immense obstacles to winning the Democratic nomination, starting with his own political baggage that includes a complex array of business entanglements, a history of making demeaning comments about women and a record of championing law enforcement policies that disproportionately targeted black and Latino men with invasive searches.
His long-delayed start in the race will leave him scrambling to catch up with some of the other candidates in building a national profile and constructing a large-scale campaign organization. As a result, he plans to mount an unconventional primary campaign, bypassing the earliest primary and caucus states, like Iowa and New Hampshire in February, and focusing instead on the delegate-rich March primaries in states such as California and Texas.
His extraordinary wealth, estimated at more than $50 billion, could, on its own, represent a political challenge. It is likely to intensify the already-raging Democratic debate about whether and how to rein in the power of the extremely rich. Senator Bernie Sanders of Vermont accused Mr. Bloomberg of “trying to buy an election” with his onslaught of television commercials, and on Saturday he described Mr. Bloomberg as a “symptom of the problem” that the wealthiest people in the country have far too much control of the government.
Perhaps to blunt that criticism, Mr. Bloomberg’s announcement video and opening advertisement included a call for the wealthy to pay more in taxes.
Mr. Bloomberg’s candidacy has the potential to reshape the primary in a number of ways, perhaps most immediately by shaking up the contest to lead the Democratic Party’s moderate wing. Former Vice President Joseph R. Biden Jr. and Mayor Pete Buttigieg of South Bend, Ind., have emerged as the leading primary candidates closer to the political center, and Mr. Biden remains the overall front-runner for the nomination. But both men have serious political vulnerabilities and neither has Mr. Bloomberg’s financial resources.
Much like Mr. Biden, Mr. Bloomberg is wagering that Democratic voters will care far more about defeating Mr. Trump than any other political or ideological consideration.
Mr. Bloomberg’s message, at the start, is leaning heavily into his biography as a business executive and as the mayor of New York City starting in the aftermath of the Sept. 11, 2001, terror attacks. His advisers acknowledge that he is far less known to voters than the leading Democratic candidates. His debut television commercial stressed his credentials as a self-made executive — “a middle-class kid who made good” — and his political advocacy on core Democratic concerns like gun control and climate change, as well as on economic development and public health issues like smoking. Those issues, his advisers say, will all be central to his candidacy.
While Mr. Bloomberg is a political moderate, his opening message also borrowed in some respects from the anti-Washington rhetoric of the Democratic Party’s populist wing, led by progressives like Mr. Sanders and Senator Elizabeth Warren of Massachusetts. “I know how to take on the powerful special interests that corrupt Washington,” Mr. Bloomberg said in his statement on Sunday. “And I know how to win.”
Gov. Gina Raimondo of Rhode Island, who helms the Democratic Governors Association, said she had spoken recently with Mr. Bloomberg and saw him as a strong candidate despite the late hour. Ms. Raimondo said the former mayor recognized he faced “long odds” in the primary, but she suggested Mr. Bloomberg could be well positioned in a general election to take on Mr. Trump’s perceived credentials as a businessman.
“Trump’s a fraud. He’s a business failure. His economic policies have failed,” Ms. Raimondo said. “He’s bad for America, and I think Bloomberg can go toe-to-toe with him on that score, and he should.”
Mr. Bloomberg has seriously explored running for president several times before, including in 2016 as an independent and earlier this year as a Democrat, but has backed away every time. But it became clear over the last few weeks that 2020 was shaping up differently, as Mr. Bloomberg took steps toward forming a candidacy unlike any he had taken in the past, including putting his name on the ballot in several primary states.
Most telling of all was a speech Mr. Bloomberg delivered in New York City last Sunday, apologizing for the stop-and-frisk policing tactics that he defended as mayor. A striking concession to the politics of the Democratic Party, Mr. Bloomberg’s speech was widely seen as an effort to pre-empt criticism of the policy in a Democratic primary in which African-American and Latino voters are likely to play a decisive role.
His ability to compete seriously for the nomination may depend in part on his ability to appeal to minority voters and less affluent whites who are among the most ideologically moderate constituencies in the Democratic coalition. It is highly uncertain whether groups like these will see a 77-year-old billionaire as a compelling alternative to Mr. Biden, who is a far more familiar figure campaigning on similar themes.
At the moment, Mr. Bloomberg appears chiefly concerned with introducing himself to a national electorate that knows relatively little about him. Howard Wolfson, one of Mr. Bloomberg’s closest advisers, said in an interview that “awareness of Mike is considerably less than other candidates,” and his campaign intended to remedy that with dispatch.
Mr. Wolfson said Mr. Bloomberg would spend freely from his fortune and would not accept campaign contributions. That means there is little chance that Mr. Bloomberg will participate in Democratic primary debates, since candidates have to accumulate a sizable number of individual campaign donors in order to qualify.
“Mike is going to spend whatever is necessary to defeat Donald Trump, because he believes the stakes couldn’t be higher,” Mr. Wolfson said. “So, whatever is necessary to defeat the president, we are going to spend.”
Mr. Bloomberg’s team has already outlined several ways it will spend money against Mr. Trump during the primary, such as funding a barrage of digital ads attacking the president and a major voter-registration drive in key swing states.
Mr. Bloomberg, who was elected mayor in 2001 as a Republican, repeatedly explored running for president as an independent candidate but eventually concluded that a candidate from outside the two-party system could not win. After registering as an independent in 2007, during his second term as mayor, Mr. Bloomberg again embraced the G.O.P. in 2009 when he persuaded the New York City Council to give him an exception to the city’s term-limits law and allow him to seek a third term, which expired in 2013.
Mr. Trump’s rise to power, however, helped push Mr. Bloomberg fully into the Democratic fold. Mr. Bloomberg spoke at the Democratic convention in 2016 to endorse Hillary Clinton, then formally registered as a Democrat during the 2018 midterm elections and spent more than $100 million that year to help Democrats take control of the House of Representatives.
Although Mr. Bloomberg ruled out challenging Mr. Trump last winter, in recent months he began to reconsider as Mr. Biden struggled to take control of the Democratic primary.
At several points this year Mr. Bloomberg voiced public criticism of some of the most progressive candidates’ policies, like proposals by Ms. Warren and Mr. Sanders to impose a new tax on the country’s largest private fortunes. On Saturday, Ms. Warren pointed to Mr. Bloomberg’s television advertising as proof of the need for a wealth tax.
Since signaling his revived interest in the presidential race, Mr. Bloomberg has made few public appearances, including a brief trip to Little Rock, Ark., in early November to file paperwork to appear on the primary ballot there. Advisers say he is likely to make a campaign trip of some kind before Thanksgiving, but no firm plans have been set.
At 77, Mr. Bloomberg is one of the oldest candidates in the race, and like Mr. Biden and Mr. Sanders he would become the oldest person ever to assume the presidency if elected. Mr. Bloomberg is also, with Mr. Sanders, one of two major candidates for the nomination who are Jewish, and either would be the first Jewish president if elected.
Should Mr. Bloomberg become the Democratic nominee, it would set up a general election between two party-switching moguls from New York City, though Mr. Bloomberg’s fortune is larger than Mr. Trump’s many times over.