BACK TO THE DEMS

Mike’s switch a hint that he’ll run for Prez in 2020

Welcome back, Mr. Bloomberg!

For the first time since 2001, former New York City Mayor Michael Bloomberg is a registered Democrat — a move that may herald a presidential run in 2020 under that party’s banner.

The billionaire philanthropist, 76 (photo), posted a photo of himself re-registering on Wednesday, writing that Dems provide “the checks and balances our nation so badly needs."

The businessman-turned-politician had famously abandoned the Democratic Party in 2001 to run for mayor as a Republican — a switch he mostly made to enhance his then long-shot chances in a race that was crowded with left-leaning candidates in a historically blue city. After his surprise win, he went on to serve for three terms — engineering a one-time exception for himself to get around the two-term cap — and in 2007 he broke with the Republican Party to register as an independent.

Speculation swirled at the time that Bloomberg was leaving the GOP to set himself up as a third-party presidential candidate in 2008.

The same presidential rumors arose in 2016, but Bloomberg stayed on the sidelines of the race, endorsing Hillary Clinton, the Democratic nominee who went on to lose to Donald Trump.

Since 2013, Bloomberg has funded and created numerous charities, some with political leanings such as Everytown for Gun Safety, a nonprofit he started and largely finances that aims to foster gun control laws in the U.S.

On Wednesday, Bloomberg said he had been a Democrat for almost all his life — and it was time to return to the fold.

"At key points in U.S. history, one of the two parties has served as a bulwark against those who threaten our Constitution," he wrote. "Two years ago at the Democratic convention, I warned of those threats."

Two months ago, reports surfaced that Bloomberg was ready to wade back into politics again — as a challenger to Trump if the Republican runs again in 2020.

“I'm working on this Nov. 6 election, and after that I'll take a look at it," he told The New York Times last month.

He also added that "it's impossible to conceive” running as a Republican.

“That's not to say I'm with the Democratic Party on everything, but I don't see how you could possibly run as a Republican,” he told the newspaper. “So if you ran, yeah, you'd have to run as a Democrat.”

Bloomberg vowed earlier this year to spend $80 million to help the Democrats take control of the House during the critical elections next month. He said last week he would give $20 million to the main Democratic Senate super PAC, according to The Washington Post.

“Republicans in Congress have had almost two years to prove they could govern responsibly. They failed,” he said in June.

The deadline to register to vote in New York State is Friday.