Even if Rubio doesn’t pick off many Trump supporters, however, his debate performance probably helped him in other respects. First, while it can be easy to overestimate how much this matters, he’ll probably succeed in changing his news coverage a bit. The media, perhaps having grown wary of Rubio’s previous overpromising, had been taking an increasingly glass-half-empty view of his candidacy. Even though Rubio had some decent news this week — the endorsements, the Bush dropout, a series of polls showing him pulling ahead of Ted Cruz in Southern states, a couple of second-place finishes — the press wasn’t having any of it. Now, at the very least, they’ll need to introduce some notes of caution, while Rubio will improve the morale of his supporters and surrogates.

Second and more importantly, Rubio emerged forcefully as the anti-Trump candidate. In contrast to his previous, sometimes passive performances, Rubio was so eager to be the alpha male on stage that he’d butt in on exchanges between Trump and Cruz in addition to picking his own fights with Trump. That sends a signal to Republican voters, donors and party elites: If you want to take down Trump, I’m your guy. These Republicans can now choose to coordinate around Rubio as an anti-Trump focal point, both in the sense of having the best chance to beat Trump and as the best conduit for attacks.

The debate could also inspire further attacks on Trump from Rubio and other Republicans.