Maybe the Democratic Party’s No. 2 was just joking about antifa violence. Or maybe he supports it.

On Wednesday, Rep. Keith Ellison (D-Minn.), the Democratic National Committee’s deputy chair, tweeted a photo of himself cheekily smiling with a copy of “Antifa: The Anti-Fascist Handbook.” His caption: “I just found the book that strike [sic] fear in the heart of @realdonaldtrump.”

Obnoxious and wrong: Violence prompts moderates to support the side being attacked against the one violating civic norms. Antifa helps Trump.

Yet it also plays well on the left, feeding fantasies of a serious threat from right-wing extremists. And Ellison, who spent years defending the odious Louis Farrakhan, is a radical who gains from that polarization.

In short, he wasn’t just trolling the right for kicks, he was baiting liberals like House Minority Leader Nancy Pelosi, who have denounced antifa’s thuggery.

When you talk about antifa, Pelosi said, “you’re not talking about the far left of the Democratic Party — they’re not even Democrats.”

Ellison plainly disagrees.