At the 2004 Republican National Convention in New York City, host and then-Mayor Michael Bloomberg implored his “fellow Republicans, Democrats and independents” to support George W. Bush for president.
At the 2016 Democratic National Convention in Philadelphia, Bloomberg said he knew what it was like to “have neither party fully represent my views or values” and urged other independents to back Hillary Clinton over “dangerous demagogue” Donald Trump.
On Wednesday, Bloomberg announced in simultaneous Instagram, Twitter and Facebook posts that he was re-registering as a Democrat.
“We need Democrats to provide the checks and balance our nation so badly needs,” he wrote.
Bloomberg, 76, returns to the party he left when he first ran for New York City mayor nearly two decades ago and in doing so has fanned rumors he is mounting a challenge to Trump in 2020.
Bloomberg has made no secret of his opposition to the president, a fellow billionaire businessman, telling CNN in September that he sees a “lack of civility and openness and honesty” in the administration.
Bloomberg switched from Democrat to Republican before his 2001 campaign for mayor, then abandoned his GOP registration in 2007 and had been a political independent until now.
“I never considered him to be a Democrat or Republican or independent. I considered him to be Mike Bloomberg," Rep. Peter King (R-Seaford) said.
Bloomberg, who co-founded the Bloomberg LP financial and media corporation and whose net worth Forbes puts at $46 billion, already has made his mark as a Democratic donor this midterm election season.
He pledged to spend $100 million toward regaining a Democratic majority in Congress, according to an adviser. Nearly $80 million of the contribution will go toward flipping the House, and $20 million will go to the Senate Majority PAC, or political action committee, the adviser said, speaking on the condition of anonymity.
But Bloomberg also hosted a fundraiser at his Upper East Side home in June for King, who said the event was indicative of Bloomberg’s pragmatism.
"I’m pretty definite that he’s thinking of running for president," said King, who has worked with Bloomberg on policing and 9/11-related issues.
Bloomberg has attracted media attention for his heavy funding and advocacy of issues that political experts say resonate with the left and center wings of the Democratic Party.
He is the United Nations special envoy for climate action and has strongly criticized Trump’s withdrawal of the United States from the Paris climate change accord. Bloomberg also co-founded Mayors Against Illegal Guns, which merged with Moms Demand Action to create Everytown for Gun Safety and works for stricter gun control laws.
Bloomberg traveled to New Hampshire on Saturday to campaign for political candidates at a Moms Demand Action event.
“The cemetery of American politics is loaded with people who have money,” said Hank Sheinkopf, a veteran Democratic strategist who worked for Bloomberg’s 2009 mayoral campaign. “Bloomberg’s gift is that he’s used his money in a particular way that frankly enamors him to portions of the Democratic Party: guns, climate change, livable cities.”
But Bloomberg would be the oldest person to assume the presidency — Trump, 70 at his inauguration, now holds that distinction — and he is a centrist at a time when the Democratic base is moving leftward, experts note.
“I think he knows how to do the politics, but I don’t know how much primary voters on the far left are going to be receptive to him,” said Basil Smikle, former New York State Democratic Party executive director and a strategist who worked on Bloomberg's 2009 campaign.
Smikle said, “I think the party as a whole, they’re going to look at him like: 'We can use your money, we can use you for fundraising, but how much can we engage you on policy issues in this climate?'”
Sheinkopf said Bloomberg’s anti-gun and pro-environment stances appeal to younger voters, and his announcement via social media helps in “obliterating the age question.” Sheinkopf also said Bloomberg’s ability to move between party lines may draw support from voters turned off by hyper-partisanship.
Trump, who like Bloomberg has changed his party affiliations in the past, has not commented on the former mayor’s move to the Democratic Party. Trump in July 2016 tweeted: “‘Little’ Michael Bloomberg, who never had the guts to run for president, knows nothing about it. His last term as Mayor was a disaster!”
Mark Green, a former New York City public advocate who as a Democratic nominee for mayor lost to Bloomberg in 2001, said he believes his former opponent is using the formula that worked for him in the past. "Switch parties tactically in order to win a nomination for executive office," Green said.
King said he would support the Republican nominee in 2020, “but I’m never going to say a bad word against Mike Bloomberg.”
John Catsimatidis, a billionaire businessman, political donor and radio host who ran as a Republican in 2013 to succeed Bloomberg and now supports Trump, also praised Bloomberg.
“He’s a fine person, he’s an honest person and I think that’s very valuable to America,” Catsimatidis said.
Catsimatidis said he and Bloomberg spoke last Wednesday at a business breakfast event.
“I think he is certainly considering it,” Catsimatidis said of a White House bid. “But there’s a lot of things he has to weigh.”
Asked about the variables, Catsimatidis answered: “The ability to win.”
Former New York City mayor
Co-founder of Bloomberg LP financial and media firm
Bloomberg's political history:
2001: Wins election as NYC mayor as a Republican, having switched from the Democratic Party
2005: Wins re-election as a Republican
2007: Leaves the Republican Party to be a political independent
2009: Wins re-election as an independent
2013: Leaves office after three terms and 12 years
Oct. 10, 2018: Announces he is re-registering with the Democratic Party