Sen. John McCain (R-Ariz.) has spoken out against bigotry and injustice during his more than 30 years in the Senate. (Thomas Johnson/The Washington Post)

Sen. John McCain (R-Ariz.), having just been diagnosed with an aggressive form of brain cancer, is returning to Washington on Tuesday to cast a vote on the Republican effort to repeal and replace the Affordable Care Act. Like the other senators, he doesn’t know what he’s voting on, because Majority Leader Mitch McConnell (R-Ky.) hasn’t revealed which version of the bill will be offered. As of this writing, rumors are flying about what kind of gambit McConnell might employ, including a “skinny repeal” that would eliminate only  the ACA’s individual mandate and some taxes. There may be votes on different versions offered up in a sequence, including “repeal and delay.” (Rand Paul says he was promised a vote on that version.) What we can say for sure is that Republicans will be voting to take health coverage away from tens of millions of people, without a single hearing or moment of expert testimony to discuss the effects of what they’re about to do.

Since we learned that McCain will be coming to the Capitol for this vote, many liberals have expressed their disgust at the idea that McCain, suffering from a terminal illness, would make one of his final acts as a senator a vote to snatch health care away from millions of Americans. Should he vote yes, he will have earned that scorn, along with every other Republican who joins him. But I want to focus on the other possible outcome. This is an opportunity, perhaps the last one, for McCain to show that he is the “maverick” journalists so often say he is.

Not only that, this vote would be exactly the kind of controversy on which McCain built that reputation, questionable though it may be.

Let’s step back for some background. McCain has always been a reliably conservative Republican — not the most conservative, but somewhere around the median for Republicans in the Senate. He occasionally votes against his party, but so do most senators, at least now and again. When I was researching a book during the 2008 election on McCain’s relationship with the press, the first instance I found in which he was referred to as a “maverick” came in a 1989 story. But it was his advocacy for campaign finance reform in the 1990s, the end result of which was the McCain-Feingold campaign finance law (almost the only significant piece of legislation he has written in a 35-year congressional career) that cemented the idea in the press’s mind that McCain was a “maverick,” a word reporters would use to describe him thousands of times in subsequent years.

That wasn’t the only high-profile bill he would break with Republicans on — there was a bill to regulate tobacco that he co-sponsored, and he voted against the Bush tax cuts (it would have been awkward not to, after he attacked Bush during the 2000 primaries for the plan). But the truth is that almost every senator breaks with his or her party from time to time. When McCain does it, however, it becomes news, and news that is mostly taken up with worshipful descriptions of this heroic man, so unlike his peers. You’ll notice that when, say, Sen. Susan Collins (R-Maine) breaks with her party, she’s called a “moderate,” not a “maverick.” In other words, it’s assumed to be a function of her ideology, not of some admirable character trait lying at the core of her being.

And when McCain does the things ordinary politicians do — shift positions to accommodate a changed political situation, or gobble up money from lobbyists, or pander to voters’ worst instincts (the onetime advocate of comprehensive immigration reform not only abandoned that position but also aired an ad in which he said that we must “complete the danged fence” on the border) — reporters either dismiss it altogether or claim that he just hates doing it, so honorable is he. The same actions that get others condemned somehow get twisted into proof of McCain’s virtue.

It is simply impossible to overestimate the love, bordering on worship, that reporters in Washington long had for McCain, and to a great degree still do. It has a number of sources — admiration for what he endured in Vietnam was critical, but even more important was the skillful way he cultivated them and played to their desires. The result of the special relationship between McCain and the press is that they have always written about him in a manner fundamentally different from how they approach other senators.

McCain understood this well — no politician in recent history has had a better grasp on what reporters are after and how to craft his image in the media. The result is that he was always treated by a fundamentally different standard than anyone else. Just to take one representative example, during her time in the Senate, Hillary Clinton occasionally broke with her party to join with Republicans on one issue or another; there were many Democrats more liberal than she. But nobody called her a “maverick” for doing so. Her motives were assumed to be cynical, but McCain’s motives are always assumed to be pure. Indeed, this separates McCain from every other politician whom journalists report on: He alone is written about as though he never considers politics or his personal advancement, but makes decisions only on the basis of his unimpeachably virtuous ideals.

But here’s the key to understanding the times McCain breaks with his party: It happens only when the GOP is on the wrong side of public opinion. The public thought campaign finance reform was a fine idea. They wanted tobacco regulated. They were indifferent to the Bush tax cuts. McCain’s “maverick” stances never carried significant risk to him, especially since he wasn’t trying to move up in the congressional leadership so he didn’t mind displeasing his GOP colleagues. His sights were always set higher, on his national ambitions. So bucking the party had nothing but benefits: It put him with the majority of the public and garnered rapturous press coverage that would only elevate his public persona.

So today, McCain has another chance to cement that image. He can go against the wishes of McConnell and President Trump, neither of whom he likes and neither of whom likes him, by voting no on a bill that has the support of fewer than 1 in 5 Americans. If he does so, history will record that he set aside his resentment of Barack Obama and played the maverick one last time. He will be cast once again as the hero of the story. He can rise above the petty cruelty of his party and say no to an utterly monstrous bill that would rob so many of the kind of care on which he now relies. He can say that getting a “win” for the party is not worth immiserating so many of his fellow citizens.

McCain can decide that now, with no more races to run and no more political costs to worry about, it’s time to do the right and righteous thing. The only question is whether he has it in him.