Bernie Sanders says it’s an “embarrassment” that so many working-class citizens bolted the Democratic party to vote for Donald Trump — and is leaving the door open for another run for the White House in 2020, when he’d be 79.

“Four years is a long time from now,” the 75-year-old Vermont senator said. “We’ll take one thing at a time, but I’m not ruling out anything.”

Sanders bemoaned the fact that so many working-class people cast their ballots for the Republican candidate, and chalked up Hillary Clinton’s loss on Tuesday to a “lack of enthusiasm” among Democrats.

“It is an embarrassment, I think, to the entire of Democratic Party that millions of white working-class people decided to vote for Mr. Trump, which suggests that the Democratic message of standing up for working people no longer holds much sway among workers in this country,” he said.

Sanders said he believes Trump is a “fraud.”

“I think despite all of his rhetoric about being a champion of the working class, it will turn out to be hollow,” he said in an interview with the Associated Press Thursday.

That was at odds with a statement Sanders issued a day before offering to work with Trump on issues that would help working families.

“Donald Trump tapped into the anger of a declining middle class that is sick and tired of establishment economics, establishment politics and the establishment media,” Sanders said in the statement.

“People are tired of working longer hours for lower wages, of seeing decent paying jobs go to China and other low-wage countries, of billionaires not paying any federal income taxes and of not being able to afford a college education for their kids — all while the very rich become much richer.”

He added:

“To the degree that Mr. Trump is serious about pursuing policies that improve the lives of working families in this country, I and other progressives are prepared to work with him. To the degree that he pursues racist, sexist, xenophobic and anti-environment policies, we will vigorously oppose him.”