I've been saying for the last few weeks that Hillary Clinton's campaign is in a window of danger. Tonight might be the moment of maximal peril.
To recap: It's highly unlikely that Clinton could lose the Democratic nomination to Bernie Sanders. Even if Sanders were to win Iowa and New Hampshire-which he has a fair chance to do—he's the equivalent of Admiral Yamamoto: Yes, I can run wild in Des Moines and Manchester for eight weeks. But then what?
No, the danger for Clinton is and always has been that she's exposed as vulnerable. And because weakness is a provocation, this exposure could lure a superior candidate into the race.
All of which is why tonight is so important: If Clinton performs badly and appears untrustworthy or wounded, unlikable or hapless, this makes it more likely that Joe Biden—or someone else—decides to jump in. Conversely, if she turns in a dominating performance where she is crisp and formidable, it could act as the brush-back pitch she's desperately needed to throw for weeks.
Here are a few things to watch for tonight:
* Anderson Cooper: As the moderator of a small group, Cooper will have a pretty large influence on the debate. Will he probe for genuine weaknesses in the group, the way the Fox News folks did at the first Republican debate? (Andrew Stiles has a list of questions Cooper should definitely ask.) Will he encourage fights the way Jake Tapper did at the second? Or will he try to keep the candidates in their own lanes? To a large degree, Clinton will be at Cooper's mercy. I bet she's just thrilled about that.
* Sanders on Clinton: How negative will The Bern be willing to go against the Democratic party's presumptive nominee? Will he go nuclear on her Iraq vote and Goldman Sachs ties? Lincoln Chafee has nothing to lose by unloading on Clinton. But if Sanders really believes he can win the nomination-sidebar: Is it possible that Sanders really believes he can win the nomination? Then he has to be more careful. He can't risk being a jerk and he'll probably want to use the debate not to take down Clinton, but to introduce himself to the broader universe of Democratic voters. Because to win the nomination, he would need a bunch of Clinton's voters.
The classic way to run against a dynastic candidate with high favorables, like Clinton, would be to run the Gold Watch Gambit, which is what Bill Clinton employed against George H.W. Bush. Instead of attacking Bush, Bill Clinton's campaign suggested to voters that President Bush was a good man, who'd made valuable contributions, but whose time was past. But that stratagem only works if you're the younger fresh face. So Sanders will have to come up with some other pitch.
* Clinton on Sanders: The former FLOTUS/Senator/Sec. State (FloSenSec? FloSenStat? They both sound like nasal sprays) isn't really debating anyone on the stage with her. Her job is shadowboxing Joe Biden and shoring up her image with party elites. So does she engage with Sanders directly? Stay above the fray? She has an awful lot to lose by getting into a tug-of-war with the darling of the progressive base.
* Clinton and the Little People: Martin O'Malley, Lincoln Chafee, and Jim Webb are all going to be on stage, too, and this is terrible for Clinton. All three of these guys will be honed in on Clinton from the start—they have no incentive to go after anyone else and no way to raise their standings except by attacking Clinton.
It'll be hard for Clinton to get the better of exchanges with these guys simply because of the stature differential: Any time Clinton has to stand there and fight off an attack from Lincoln Chafee—a man of no political consequence and with no political future—she's already lost.
So all in all, Clinton's downside potential tonight is pretty significant. But so is her upside.
The picture I've painted so far isn't actually Clinton's worst-case scenario. Truth is, she can look shifty and robotic and inauthentic. And her position is strong enough that she can take her lumps on Iraq and her swerve on the TPP. It might not be pretty, but she can live with looking like the second coming of Nixon.