Joe Biden has a huge hurdle to clear if he intends to take up residence in the White House in January 2021.

The former vice president must defeat an enormous field of Democratic opponents vying for their party’s nomination; then if he succeeds at that he will have to defeat Donald Trump in the general election.

The ex-VP’s opening gambit, released this morning via video, goes straight after Trump. I have to hand it to Biden. He is acting like the Democratic front runner.

Biden’s video takes dead aim at the president’s hideous comment about “fine people . . . on both sides” of the Charlottesville, Va., riot that erupted in 2017. One of those “sides,” let us recall, comprised neo-Nazis, white supremacists and Ku Klux Klansmen. Biden noted in his campaign video that Trump sought to attach “moral equivalence” between haters and those who protested against them.

That was the moment, Biden said, that he realized the nation was facing the worst threat he has seen “in my lifetime.”

Biden’s front-running status is likely to diminish as his fellow Democrats start picking away at his huge public service record. It contains more than a few missteps, mistakes, misstatements and assorted gaffes along the way.

For now, though, the former vice president has decided that his No. 1 happens to be the current president of the United States.

To which I say: Give him hell, Joe!