New York business tycoon Michael Bloomberg paved the way for a shot at the US presidency, registering as a candidate in the Alabama Democratic primary race before Friday's filing deadline. Although the billionaire has not publicly announced his run, his inclusion among a crowded field keeps his options open for mounting a concerted bid to topple fellow New Yorker Donald Trump.
His name was posted among 17 candidates on the Alabama Democratic Party's website only hours before registration closed.
The decision to run would be an about-turn for Bloomberg, 77, who announced in March that he would not seek the White House.
Ranked by Forbes as the eighth-richest American with an estimated worth of US$53.4 billion, his potential bid drew immediate criticism that he was just another wealthy businessman trying to buy an election.
Bloomberg also will face questions about his record as a three-term mayor of New York, particularly from the Democratic Party's vocal progressive wing, and about why he is needed in a race that still has 17 candidates vying to challenge Republican President Donald Trump in November 2020.
There is no constituency for Michael Bloomberg that isn't already taken by one of the candidates who are already running, said Charles Chamberlain, chair of the Vermont-based progressive group Democracy for America.
But Bloomberg is skeptical that any of the current candidates can beat Trump, according to a spokesman.
Opinion polls show three contenders battling at the top of the Democratic race: US Senators Elizabeth Warren of Massachusetts and Bernie Sanders of Vermont, who lead the progressive wing, and moderate Joe Biden, the former vice president.
Bloomberg has been critical of Warren and her desire to institute a tax on the super-wealthy, which she would use to fund programs ranging from universal healthcare to free college tuition.
Biden, meanwhile, has turned in uneven debate performances and lagged behind his top rivals in fundraising. Bloomberg would likely seek to appeal to the same moderate voters drawn to Biden.
Public opinion polls show most Democrats do not share Bloomberg's dissatisfaction with the contenders. A Monmouth University poll taken in late October and early November found three-fourths of Democrats were satisfied with their choice of candidates and just 16% wanted someone else.
Trump weighed in Friday on a potential Bloomberg bid.
Little Michael will fail, Trump told reporters in a reference to the stature of the 5ft, 8in (1.73m) Bloomberg. He doesn't have the magic to do well.
There's nobody I'd rather run against than little Michael, Trump added. He's not going to do well but I think he's going to hurt Biden actually.”