At last, Bernie Sanders is going after Hillary Clinton’s worst flaw — her character.

The Vermonter lambasted the Democratic front-runner in a Wall Street Journal interview Wednesday.

Sanders didn’t just note Clinton’s flip-flops on countless issues. He put the e-mail issue back on the table, saying her lack of transparency and possible compromising of classified material are “valid questions.”

That’s a big switch from last month, when he got big applause by saying everyone is tired of hearing about her “damn e-mails.”

Maybe Sanders realized what a lost opportunity that was. Clinton’s been proving herself untrustworthy for years. It’s political malpractice not to use that ammo.

Team Hillary answered by going nuclear. Where last week the Clinton camp was calling Sanders sexist, now it’s hinting he’s racist. He contrasted “rural” and “urban” views on guns; that, goes the charge, was code about whites vs. blacks.

If you want the nomination, Bernie, don’t fight with one hand tied. Hillary’s not going to hold anything back.

It helps that you can land your hardest hits just by bringing up . . . the truth.