BE AFRAID: Bob McManus: ‘President Bloomberg’ could actually happen.

America’s perpetual presidential campaign is on the upswing, with Democratic national chairman Tom Perez wondering about how best to sort out an oversized candidate field that ranges from left to hard-left to even-harder left.

And then there is Mike Bloomberg.

The fellow formerly known as Mayor Mike has had big eyes for the Oval Office since forever but never quite could bring himself to — excuse the expression — pull the trigger.

This time, he’s 77, richer than Croesus, not at all bashful about spending his dough and clearly hearing the clock tick. There will be no next time.

So the question is whether America’s prepared to ditch full-fat donuts. Or, to paraphrase a reason he gave for not running last time, to see whether the country is ready to install a short Jewish man from New York in the White House.

Conventional wisdom would suggest that it is not. His New York address and identification with liberal causes have much more to do with it than his religion, though that’s a factor, too.

Then again, conventional wisdom couldn’t have been more wrong about another ­unlikely New Yorker two years ago: Donald Trump of Fifth Avenue, by way of Queens. Meanwhile, Hillary Clinton was inevitable — until she wasn’t.

Now the wise ones are suggesting that Trump is toast, which isn’t necessarily true, but the possibility is strong enough to attract an infantry platoon of folks happy to dance on Clinton’s (figurative, centrist) grave, most entering from stage left and most distinguishable from the others only at the margins.

Really. After the vaporware candidates — the likes of Kirsten Gillibrand of New York, Beto O’Rourke of Texas or Cory Booker of New Jersey — are culled, what really differentiates former Vice President Joe Biden from Bernie Sanders of Vermont from Liz Warren of Massachusetts from Kamala Harris of California?

Rhetoric is all. They are from deep-blue states, they have virtually no executive experience — and they are poor as church mice.

Thus, the blue-state bit aside, Bloomberg is a singular presence: He is worth a breathtaking $51 billion going into the latest stock-market gyrations, and when it comes to spending on ­behalf of his perceived best interests, Scrooge he isn’t.

I remember when money in politics was bad. But I’m sure if Bloomberg gets the Democratic nomination, the papers will be filled with high-minded encomia to the principled independence that great wealth can bring.