JOE BATTENFELD: Democrats’ circular firing squad must have made Trump smile.

The crowd visibly gasped at the answer while Elizabeth Warren — who just days ago put herself out as the great unifier of the party — launched the strongest attacks on Bloomberg of anyone on stage.

“Democrats take a huge risk if we just substitute one arrogant billionaire for another,” Warren said in one of several roundhouse blows aimed at Bloomberg.

Warren didn’t stop there — going after Pete Buttigieg and even Sen. Amy Klobuchar’s health care plans, referring to Buttigieg’s plan as a “PowerPoint presentation” and Klobuchar’s plan a “Post-it note.”

Slumping in the polls and trying to recover from her disastrous fourth-place showing in New Hampshire, Warren took wild swings at her opponents all night. . . .

It was an ugly night all around for Democrats, and Trump had to be smiling if he was watching.

Democrats have a long way to go to unify their party and defeat Trump, and that was the real takeaway from this debate.

Related: “In what can only be described as a demolition derby—with a bunch of amped-up Yugos crashing into each, other over and over again, until engine fires forced the drivers out onto their roofs while sirens blared—Democrats took to the stage to eviscerate one another and pave the way for Trump’s reelection. . . . Not only did Dems unselfconsciously brag about their Marxist/socialist plans, but they displayed their utter contempt for capitalism. When Bloomberg tried to defend the economic system that has raised more people out of poverty than any system in the history of the world, the other candidates on the stage groaned—and many in the audience booed.”

Meanwhile, Trump’s rally in Arizona last night was filled with love.

UPDATE: