Like the swallows coming back to Capistrano, reports are surfacing that Michael Bloomberg is considering a White House run. Again.

The former New York mayor dipped his toes into the water in both 2012 and 2016, and backed off a 2020 race last March. Always for the same reason: He concluded he couldn’t win.

He was right and many actual candidates should follow Bloomberg’s example. The 12 Democrats on the debate stage last week proved that quantity does not guarantee quality.

Yet a new reality is prompting Bloomy’s second thoughts. It is the growing likelihood that Sen. Elizabeth Warren, an extreme leftist, will win the nomination and guide the party into the political wilderness.

Bloomberg, a Democrat again after being a Republican and independent, regards Warren’s economic plans as dangerous nonsense. He told her as much at a gun control event he bankrolled.

Taking the microphone after her, he told the audience, “I just said to Senator Warren on the way out, ‘Senator, congratulations, it’s a nice talk. But let me just remind you if my company hadn’t been successful, we wouldn’t be here today, so enough with this stuff.’ ”

Earlier, he denounced her plan for a wealth tax, saying, “It’s called Venezuela.”

Bloomberg’s reconsideration, reported by CNBC, comes with a hitch. He’s said to be holding back until Joe Biden craters or quits.

Big mistake because by that point, it will be too late.

It’s true that Biden is an impediment to others, which is why I urged him to drop out a month ago. My point then was that no other relative centrists, including Bloom­berg, would run because none could beat Biden in the primary.

But at the same time, it was already clear that the former vice president can’t go the distance and win the nomination. His early ­debate performances were dreadful and his inability to finish a sentence without veering into gibberish is painful to watch.

And that was before President Trump’s focus on the fact that ­Biden’s son Hunter made millions from foreign governments while his father was vice president.

The many blows on Joe Biden are having an impact. Warren has overtaken him in most polls and is now the party’s recognized front-runner. His donors also are getting skittish, with the most recent fundraising report showing Biden trailing Warren, Sen. Bernie Sanders and even Pete Buttigieg.

Still, because Dem voters are divided among the large field, Biden could limp along well into the primary season, which starts with the Iowa caucus on Feb. 3 and includes Super Tuesday just a month later.

At some point, he will collapse, but there probably will not be enough time for a newcomer to get into the race and amass the delegates needed to stop Warren.

Which is why Bloomberg should take the plunge now. Later will be too late.

Besides, he’s 77 years old and, his megabillions notwithstanding, he’s not getting any younger. If not now, when?

This is not an endorsement, certainly not for the general election. Trump’s economic policies are boosting incomes and opportunities for tens of millions of people and his America First agenda is a road map for national renewal. Assuming the president stops shooting himself in the foot, he will be a formidable opponent.

But America needs two viable parties competing for many of the same voters to make our system of checks and balances a governing reality. These days, the Democratic Party is veering too far left under the leadership of arrogant coastal elites who are hostile to free speech, religion and the everyday concerns of working- and middle-class citizens.

The sophomoric idiocy of Rep. Alexandria Ocasio-Cortez and her anti-Semitic pals would be laughable if they weren’t serious power players driving much of the party’s agenda. Their support for impeachment helped push Speaker Nancy Pelosi down that destructive road.

Warren is smarter but not ideologically different. Her claim to be a capitalist is as phony as her claim to have American Indian heritage.

Hiding behind a fig leaf of seeking fairness, she is fixated on taking away private health insurance and imposing massive tax hikes on individual and corporate wealth. As one of her opponents correctly charges, Warren wants to use government power to penalize and punish Americans rather than help lift them up.

Her job-killing policies must be challenged by a credible candidate from within the party and Bloomberg is uniquely qualified for that role.

His three-term mayoralty was a huge success as he guided New York out of the dark aftermath of 9/11 into a new golden age of safety and prosperity. He is one of the great business minds of our era and his philanthropy is a model for generosity, even as much of it is directed at such political issues as gun control, abortion rights and fossil fuels.

Alas, like most wealthy people who preach the evils of climate change, Bloomy’s personal carbon footprint is gigantic, with mansions galore and a private fleet of aircraft.

While Bloomberg tells friends he doesn’t believe there is any place for him in the campaign, he would shake up the race and give voters a sensible alternative. He’s got a team eager to go and money would be no object, allowing him to make the case that he knows how to run a government and will do for the nation what he did for New York.

As he put it in a Washington Post op-ed last week: “The presidential aspirants are not short on big ideas. But voters must demand they explain how they intend to move from proposing plans to actually implementing them, including passing them through Congress. Those who dodge the question by speaking of revolution and the bully pulpit aren’t up to the job.”

That sounds like a campaign speech. But it’s either now or never.

RUSSIA again, Hill?

Hillary Clinton sounds like the late Sen. Joe McCarthy. His habit of seeing Communists behind every tree is echoed by Clinton’s habit of accusing her opponents of working for Russia.

The 2016 loser, who still says Trump used Russia to steal the election, now accuses Rep. Tulsi Gabbard (D-Hawaii) of being “groomed” by Vladimir Putin and says Green Party candidate Jill Stein is a “Russian asset.”

Both women fired back, with Stein accusing Clinton of slander and Gabbard calling her “the queen of warmongers, embodiment of corruption, and personification of the rot that has sickened the Democratic Party.”

Amen to all that.

Enough of Thrive jive

Reader Michael Castagna is livid at the cost and uselessness of City Hall’s Thrive program. He writes:

“Thrive should set up an office in every homeless shelter, prison, halfway house, court building, hospital and any place frequented by the homeless. Every precinct should have a contact person for a Thrive agent.

“Until then, stop spending money to ‘have a conversation.’ And stop pretending to care about the mentally ill.”