Bill de Blasio should have seen it from the beginning.

New York City residents don’t think much of him. Yet the mayor decided he wanted an upgrade, to become the next president of the United States.

De Blasio never got to 2 percent in any national poll among Democratic candidates for president. So, today he pulled out. He’s done.

My hope is that de Blasio’s decision will trigger more withdrawals from the lengthy list of never-will-win Democrats seeking to win their party’s 2020 presidential nomination.

De Blasio didn’t qualify for the latest Democratic joint appearance in Houston, which I suppose was the last straw. The hard truth for the mayor was that a man who couldn’t engender broad support within his own city wasn’t likely to do any better on the national stage.

I reckon the still monstrous Democratic field has more candidates who will pack it in. They’ll leave this race to the half-dozen or so who actually have a chance in hell of being nominated and then running against the huckster in chief, Donald Trump.

Call it a campaign, folks. Follow the NYC mayor’s lead and go home.