CLEVELAND — President Barack Obama ridiculed Republican Donald Trump’s bid to cast himself as a populist Friday, saying that before entering the race the real-estate mogul was a “guy who spent all his time trying to convince everybody he was a global elite” and a star.

Campaigning for fellow Democrat Hillary Clinton, Obama said Trump is trying to dupe voters into believing that he supports the working class. “Don’t fall for it,” Obama told the crowd of thousands who gathered on the tarmac of a small airport along the shore of Lake Erie.

“This is a guy who spent 70 years on this earth with no record of supporting workers . . . Then, suddenly he’s going to be the champion of the working community? C’mon, man!” Obama said about Trump, the Republican candidate to succeed him. “This is a guy who spent all his time trying to convince everybody he was a global elite, flying all around . . . Now, he’s trying to be a populist? C’mon, man!”

The president added: “You want to know what someone’s going to do? Look at what they’ve been doing their whole lives.”

Obama’s comments apparently were aimed at Trump’s claim to be the lone candidate fighting for the “little guy” and the Republican’s assertions that “global interests” were working against him.

Obama, now in the final 11 weeks of his presidency, has been stumping for Clinton in this key swing state where early voting is under way. Former President Bill Clinton was campaigning in the state as well, headlining a Cincinnati rally; Hillary Clinton didn’t campaign Friday.

Obama’s two-pronged message: Don’t get discouraged by the low campaign rhetoric and sit out the election; and Clinton has great qualifications while Trump has none.

advertisement | advertise on newsday

“Don’t fall for the easy cynicism that your vote doesn’t matter,” Obama said. “Equality is on the ballot . . . Democracy is on the ballot.”

Obama assailed Trump’s campaign rhetoric, saying the Republican’s threats to jail his opponent, ban the media or declare an election rigged were things that happen in a tyrannical nation and had no place “in the world’s greatest democracy.”

“In a democracy, you can’t just threaten to jail your opponent,” Obama said.

He repeated his view that Trump was “unfit” to be president and compared him unfavorably to the two previous Republican presidential candidates, Sen. John McCain (R-Ariz.) and former Massachusetts Gov. Mitt Romney.

“I could have seen them serving us honorably, representing us on the world stage,” Obama said. “That’s not the case with today’s nominee.”

But he took the Republican Party to task, too, saying it “just allowed a lot of crazy talk to be pumped out” over the last 10 years, firing up its base of voters but setting the stage for Trump to be its candidate.

“Conspiracy theories: I was born outside of this country. Hillary and I started ISIL. We’re going to impose martial law . . . and crazier stuff than that,” Obama said.

“Donald Trump didn’t build this crazy conspiracy stuff,” Obama said. “Republicans stood by silently . . . Now that some are walking away [from Trump], I ask: ‘Why’d it take you so long?”