Give the Donald credit. He not only has driven a deep divide within his own party, he has also done his best to heal the divisions in the opposing party. Quite the feat.

Of course, it’s all in a day’s work for Trump, who is, I think we can safely say, a candidate like no other. At least, that’s the way to root.

We know all about Trump v. Ryan and Trump v. Erickson, Trump v. National Review, Trump v. Romney, Trump v. All the Bushes (even Barbara), Trump v. Will/Krauthammer/Rubin/Brooks/Parker et al.

There’s a headline in Politico that sort of sums up the situation: “Trump, pivoting to general, lashes out at everyone.” But none of that may compare to the heavyweight matchup everyone has been awaiting — Trump v. Warren, Bully v. Goofy, Twitter champ v. Twitter challenger.

It’s on. And don’t expect it to end until at least November, Trump hitting Warren on the Native American charge that failed Scott Brown, Warren hitting Trump for being, well, Trump.

Donald J. Trump ‎@realDonaldTrump: Goofy Elizabeth Warren is weak and ineffective. Does nothing. All talk, no action — maybe her Native American name?

Elizabeth Warren ‎@elizabethforma: “Goofy,” @realDonaldTrump? For a guy with “the best words” that’s a pretty lame nickname. Weak!

Donald J. Trump @realDonaldTrump: I hope corrupt Hillary Clinton chooses goofy Elizabeth Warren as her running mate. I will defeat them both.

Elizabeth Warren @elizabethforma: I called out @realDonaldTrump on Tuesday. 45 million saw it. He’s so confident about his “counter punch” he waited until Friday night. Lame.

This is bad for Trump, bad for Bernie — who had long hoped for Warren’s support — and a gift to Hillary, who doesn’t need Warren to defend her. She needs Warren to attack Trump and make it clear where the political energy for all right-thinking (and a significant part of right-wing thinking) must go.

Once upon a time, Warren, liberal firebrand beloved of the anti-Wall-Street left, dominated the presidential campaign by not getting in. She could have saved the party, the thinking went, from Clinton and all her baggage, except that Warren, a first-term senator, decided to sit things out. She thought about it — she thought hard about it — but left it to Bernie, who began as a message candidate and watched in disbelief, as we all did, as his social-democratic message morphed into a cause attracting millions.

But you know how it is with causes. It may be all over but the counting, but Bernie, now reduced to wooing establishment-driven super delegates who will never support him, can’t quite bring himself to leave the race, and his millions of Bernie boosters don’t want him to go. And after his shocking success, you can hardly blame Sanders for thinking the race is also about him, or at least about everything he stands for. Because it has been.

But Warren, or as my friend Charlie Pierce calls her, Senator Professor Warren, has changed the rules.

In a series of tweets – the Trumpian communication of choice — she has changed all the cause factors. The race is now about stopping Trump, who is just that noxious, and if you believe the latest swing-state polls, just that dangerous. The betting in this race is that Clinton should win easily. The betting, however, seems to ignore recent history, in which Trump proved you don’t need money to win, or pollsters to win, or demographics to win, or policy to win, but, rather, just some old-fashioned misogynistic, xenophobic, authoritarian demagogy (and some other big words they use at the really good schools) with a little love for Putin and a taste of Mussolini thrown in.

It’s no wonder the long line line of Republicans couldn’t touch him (or that another long line is walking away from him). The media, when not celebrating him, couldn’t do any better. The fact-checkers routinely called him a liar, but, once again, facts have failed us. That’s the anti-fact era in which we live and one in which a Trump could thrive.

Can Warren do better? (Quick answer: Um, yes.) Just look how she uses Trump Twitter language to mock him. Sad.

If you’d ever seen her in action as a law professor, you’d know what Trump is up against. If you’ve watched or read The Paper Chase, you have some idea. My daughter the law professor (who, full disclosure, was once Warren’s student and who graduated to become a Warren mentee) once called Warren’s class “a cold intellectual shower first thing in the morning.” She’s not surly like Cruz or low energy like Bush or he-should-keep-his-hands-in-his-pockets like Rubio. She’s the high-energy, high-intellect interrogator who already has Trump’s full attention.

And what she has effectively said is that it’s time to move past whatever is left of the Democratic primary and concentrate on the Donald, because stopping Trump is all that really matters.

You’ve already seen it working. While Trump should be prepping for the big meeting with Paul Ryan, he’s drunk-tweeting (that’s drunk-with-power; Donald doesn’t drink) with Warren. I read in The New York Times that one Trump ally said he had to stop chasing whatever shiny object goes down the rabbit hole. And another said he had to stop punching down.

But Warren is irresistible. She hits Trump where he lives. Trump has no choice but to hit back. And Warren, who loves the rough and tumble, will counter-counter-punch. This thing will definitely go the full 15 rounds.

Maybe it’s Warren’s audition for a Clinton vice-presidential role, although it’s far from certain she’d take it. Maybe it’s to force Clinton and possibly a newly Democratic Senate to focus on income inequality and Wall Street excess and a stagnant middle class and the other progressive issues that matter. Or maybe it’s because she thinks Trump represents everything that’s not great about America.