NEW YORK - Former New York City Mayor Michael Bloomberg - a onetime moderate Republican - is considering throwing $1 billion of his vast fortune into an independent, stop-Donald Trump bid for president, The New York Times reported Saturday.

Bloomberg, 73, who is currently United Nations Secretary-General Ban Ki-moon’s Special Envoy on Climate Change, has set March as a deadline and his decision will likely be contingent on the results of early primary polls. His advisers and associates told the Times that Bloomberg was galled by the dominance of Trump, a fellow billionaire, of the Republican Patrty, and troubled by former Secretary of State Hillary Clinton’s stumbles and the rise of Senator Bernie Sanders, a leftist, on the Democratic side.

Bloomberg has in the past contemplated running for the White House on a third-party ticket, but always concluded he could not win. A confluence of unlikely events in the 2016 election, however, has given new impetus to his presidential aspirations. The two-term former mayor, who governed with a middle-of-the-road philosophy of social liberalism and low-tax conservatism, has struggled to gain political traction since leaving office in 2013. Bloomberg spent tens of millions in an unsuccessful bid to toughen the nation’s gun control laws in the wake of the Newtown, Connecticut, school shootings and many gun rights activists claim his name alone created a backlash that helped sink his cause.

The Times said Bloomberg has already taken concrete steps toward a possible campaign, and has indicated to friends and allies that he would be willing to spend at least $1 billion of his fortune on it. He has retained a consultant to help him explore getting his name on those ballots, and his aides have done a detailed study of past third-party bids. Bloomberg also commissioned a poll in December to see how he might fare against Trump and Mrs. Clinton, and he intends to conduct another round of polling after the New Hampshire primary on Feb. 9 to gauge whether there is indeed an opening for him, according to two people familiar with his intentions.

Bloomberg’s aides are reported to have sketched out one version of a campaign plan that would have the former mayor, a low-key and cerebral personality, deliver a series of detailed policy speeches, backed by an intense television advertising campaign that would introduce him to voters around the country as a technocratic problem-solver and self-made businessman who understands the economy and who built a bipartisan administration in New York.

But Bloomberg would face daunting and perhaps insurmountable obstacles in a presidential campaign: No independent candidate has ever been elected to the White House, and  his close Wall Street ties and liberal social views, including his strong support for abortion rights and gun control, could repel voters on the left and right. At the same time, his possible candidacy also underscores the volatility of a presidential race that could be thrown into further turmoil by a wild-card candidate like Bloomberg.If Republicans were to nominate Trump or Senator Ted Cruz, a hard-line conservative, and Democrats were to pick Sanders, Bloomberg - who changed his party affiliation to independent in 2007 — has told allies he would be likely to run.