We know what he does badly. He lies. He is willfully and woefully ignorant about the world. He lies. He is vain, volatile and thin-skinned. He lies. His leadership style is chaotic, unpredictable and incompetent. He lies. His chumminess with Putin is suspicious. He lies. He has no principles, character or sense of decency. And he lies.

But he is extraordinarily good at one thing. He is the greatest attack artist in politics today. Maybe of all time.

He has a feral instinct for the jugular. He has a bully’s instinct for a weak spot. He is willing to go way farther, swing more wildly and attack more viciously than anybody else.

He picks a fight with one person or with a group – the media, the Senate, Muslims. He makes it personal. He makes it Him Vs. Them. He makes us choose sides. And, as Carter says, voters today often have to choose between two sides they don’t like.

Trump’s approval ratings may be down. But you don’t run against approval ratings. You run against opponents.

There have been good attackers in politics. Nixon was good. Jesse Helms was good. But they were pussycats to Trump’s tiger.

Case in point last weekend: “Interesting to watch Connecticut Senator Richard Blumenthal taking about hoax Russian collusion when he was a phony Vietnam con artist!”

He calls Senator Elizabeth Warren “Pocahontas.” One by one in the campaign, he picked off “Low Energy Jeb,” “Little Mario,” Lyin’ Ted” and “Crooked Hillary.”

It worked. It got him to the White House. And it will keep him there unless somebody takes him down.

To be the champ, you have to beat the champ.

Beating Trump will take somebody with wit, style and steel. A JFK, an Obama, a (Bill) Clinton.

Who can do it? Who can take him mano a mano – or womano a mano?

Who can be the Joseph Welch to Trump’s Joe McCarthy: “At long last, have you left no sense of decency?”