Read more of Slate's First Mates series about the marriages of presidential candidates.
Their friends are split on how aware she ever really let herself be of his philandering over the years. Having developed a high threshold for pain before she ever laid eyes on Bill, Hillary learned from her mother both incredible toughness and coping strategies that mostly involved refusal to acknowledge unpleasantness. During their Arkansas years, one of her ways of sidestepping bad news of all kinds was simply refusing to read the papers. After the Gennifer Flowers story came out during her husband's '92 presidential run, her response, according to Carl Bernstein, was to throw herself into efforts to discredit Flowers and to try to persuade horrified campaign aides to bring out rumors that Poppy Bush had not always been faithful to Barbara. She never so much as cracked open the Starr Report, according to her autobiography.
Strangely, what Hillary seems to have exaggerated about her marriage is not how well they mended it after Monica—but how serious a breach there ever was. Even when strains were visible—or seemed to be, as when they walked to Marine One with Chelsea in between them after the news broke—in private they for the most part seemed inconceivably at ease. So that if there was any posturing for public consumption going on, it was not in the way we might think. At the time, the word put out by Hillaryland was that the president was in the doghouse and had to win her back. But if that was true, his probationary period was over almost before it began. Peter King, the Republican congressman from Long Island who was working closely with Bill Clinton on the Irish peace process at the time, recalls dreading a trip to Moscow and Ireland that he, Sen. Pete Domenici, and Rep. Steny Hoyer were taking with the Clintons right after the post-Monica Martha's Vineyard vacation that everyone assumed had been a disaster: "We were leaving from Andrews [Air Force Base], and they were coming directly from Martha's Vineyard, and everybody was kind of nervous because no one knew what to expect. But they came on the plane like the two happiest people in the world, laughing and joking, and it seemed legit. They came holding hands and kidding each other. Steny likes to sleep on the floor on the plane, and she's joking, 'They're going to say we're sleeping with Steny.' I've seen people trying to pretend everything's great when it isn't, and it wasn't that; it wasn't forced."
King voted against Clinton's impeachment and spoke to him regularly during that period. He says mending fences with his wife seemed like the last thing on the president's mind. "I had maybe 20 conversations about impeachment and five seconds were about her. He'd say, 'I've gotta work it out with this Senator and that one, and, yeah, with Hillary, too.' " Which King took not as evidence that the president didn't care, but that she didn't particularly need propping up: "He made it sound like she was being pretty decent about it. I'm not into psychobabble, but whatever complexities they have, it is not an arrangement; they seem to need each other's reassurance."
A friend of mine who is a therapist notes that for people who either were raised by a highly critical parent, like Hillary's dad, or were inappropriately enmeshed in messy grown-up problems, as Bill was, it's run-of-the-mill to wind up more comfortable in a relationship when triangulating—yes, that was the word she used—with some third party or crusade or common enemy to take the pressure off the primary relationship. At this moment in their lives, they are certainly united in their anger. Though in the past aides found him lighter and her less trusting, he's grown more like his wife in that regard in recent years.
And in this campaign, they've come full circle, with him overreacting to perceived slights and her marching on, head aloft no matter what. Their longtime friend Max Brantley, editor of the alt-weekly Arkansas Times, even gives the press corps backhanded credit for lighting the candles, pouring the champagne, and locking them in the bunker—where they do best together: "My sense is they may be closer than ever. They're embattled and really haven't gotten a fair shake in the media, and that's drawn them together. They've made a mistake whining about it—that's not how the game is played. … But they're in the Alamo, and it's a common-purpose kind of thing."
Should Hillary prevail, of course, Bill will have his restoration and she her turn. Should she lose, they will almost certainly try again in four or eight years. To ask what would keep them together in the absence of a presidential campaign is the wrong question. Because win or lose, the campaign for their dual, inextricably intertwined legacy will never be over. And, win or lose, they'll fight on together.