In September 1967, George Romney, at the time the governor of Michigan and a frontrunner for his party’s presidential nomination for 1968, gave a famous (or infamous) interview about a trip he took to Vietnam. Romney had supported the war at the time of that trip, in 1965. But by 1967, he was against it—pretty impressively early, and well ahead of public opinion.

At the time, Romney had a reputation as a flip-flopper, so the interviewer, from a Detroit news station, asked him if he hadn’t flip-flopped on Vietnam. That was when Romney uttered the line that he’d been given a “brainwashing” by U.S. generals. That one word—resonant in a culture that at the time was marinating in Cold War, Manchurian Candidate-esque paranoia—ended his career.

But here’s the thing. While the standard historical interpretation of Romney’s remark has been to mark it as one of the great political gaffes of all time, the fact is that about the Vietnam War, he was right. The war was a moral and tactical disaster. And he was way ahead of the Republican base. He sabotaged his own political future, but he told the truth.

And now here we are, 50-plus years later, and exactly the same situation confronts his son. He can tell the truth now too. He also will be sabotaging his political career. And the country needs him to—it needs him to become The Great Republican Truth-Teller About Trump. Will he do it?

As you know, Mitt Romney and Donald Trump are going at it hard now. Last Friday, Romney tweeted:

Sunday, Trump fired back with the instantly infamous “pompous ass” crack:

In addition, Trump, who never misses a shot at projecting his crimes onto others, called for Romney to be impeached:

If that’s not a declaration of political war, never mind that senators can’t be impeached, I don’t know what is.

This is a crucial week in this war. Romney must not back down. This is how Trump always wins. He bullies and cows people, and they tuck tail. Romney and other Republicans have histories of using pretty tough words and then retreating into laughter and forgetting.

Not this time. He has a chance here to show that Trump’s MO doesn’t always work. That you can punch a bully back, and he won’t know what to do.

Trump is surely right that there are a lot of Utah Republicans who are mad at Romney for daring to speak ill of the emperor. They’re a pretty extreme bunch—remember, they dumped a longtime incumbent senator, Robert Bennett, for an extremist Tea Partier, Mike Lee, in 2010. And they did it not by ballot but at a party nominating convention—the kind of event that longtime incumbents are supposed to have wired to the teeth. So I’m sure there are many thousands of jumpy Trumpies out there who are furious at Mitt.

On the other hand, Trump isn’t that popular in the state overall. He’s slightly underwater, in fact. Utah is very Republican, but it’s not Alabama. The LDSers are different. Bless their old-fashioned hearts, they—unlike, conspicuously, Christian evangelicals—actually expect integrity in their public servants. As far as Utah is concerned, I bet Romney can win a fight with Trump, in terms of public opinion, although he might well lose a renomination fight at a state party convention to a Trumpie, just as Bennett lost to a Tea Partier.

But you know what, so what? He’s 72. He’s worth a bajillion dollars. He doesn’t need this. He could spend another term or two in the Senate, but doing… what?

Voting the party line as enforced by Mitch McConnell or whatever other creature who succeeds him? Betraying his own principles and instincts, which are conservative to be sure but not right-wing and not nihilistic and instead inclined toward actual compromise and getting things done? Romney needs to realize that he will not be able to do those things in today’s Senate. It’s over. Over. But these people are often slow to recognize a reality that’s obvious to everyone outside. See Susan Collins.

No—history is grabbing Romney by the lapels and screaming at him: Choose! He knows that the president is a liar and a destroyer. He knows Trump has no morality.

I bet, however, he looks at what happened to his father and thinks: History doesn’t reward the telling of truths. But in his father’s case, that was because he told the truth somewhat by accident—the word “brainwashing” just kind of tumbled out of his mouth. The son would be doing it by design. Big difference. History rewards that, every time.

Mind you, the here and now usually does not. So Mitt Romney may pay a price for becoming the truth-teller. And it may not make much of a difference—to the GOP base, say, which is inclined not to listen to him. But he just might embolden a few of his Senate colleagues whose desertion from the Trump ranks will make a difference. In fact, that may be a job, persuading other Republicans to speak out, that only he can do.

I’m betting you’ve all seen this old photo, which has been recirculating lately:

It’s chilling, the looks on Trump and Romney’s faces. They’re Al Pacino and Keanu Reeves in The Devil’s Advocate. I don’t think I need to tell you which one is which.

When it counted, Reeves said no and broke Pacino’s spell. That was a movie, and this is life. But Romney actually has more freedom to act than Reeves’ character did. He’ll be fine. It may not even end his career. A Democratic president could give him a nice ambassadorship or something as a reward for doing the right thing.

I don’t doubt Romney knows what the right thing is. Will he do it?