Marco Rubio eked out a second place finish in South Carolina on Saturday, topping Ted Cruz by two-tenths of a percentage point (and losing to Donald Trump by a full 10). Rubio’s consolation prize, though, arrived while the votes were still being tallied: Jeb Bush called it quits. “After tonight, this has become a three-person race,” Rubio told a crowd of cheering supporters at his primary night rally, “and we will win the nomination.”

It makes sense that Rubio would think this. If you combine the primary votes received by the so-called “establishment lane” candidates—Rubio, Bush, John Kasich, and Chris Christie—this year, that Franken-candidate would have squeezed out a win in Iowa by 2 points over Cruz, coasted to victory in New Hampshire by nearly 10 points over Trump, and bested the field in South Carolina by more than 5 points. Even in a year defined by anti-establishment anger, there appear to be more than enough voters willing to pull the lever for an establishment-minded candidate to deny Trump or Cruz the Republican nomination.

There’s a major problem with the consolidation theory, though—and it’s not just that Kasich is still in the race. It’s that there’s no evidence that supporters will move en masse from one establishment candidate to another. In the most recent NBC News/SurveyMonkey national poll—taken before South Carolina—respondents were asked to name their second-choice candidate, and as it turns out, last week’s Bush backers aren’t necessarily this week’s Rubio supporters. Only 19 percent of Bush supporters said they’d switch their support to Rubio, while 16 percent said they’d go to Kasich, 12 percent to Cruz, 11 percent to Trump, and 9 percent to Ben Carson. (Roughly a quarter said they didn’t know who their second choice was.) Even if we want to be generous and assign all of the Bush backers who named Kasich as their backup plan instead to Rubio under the theory that the Ohio governor will soon drop out as well, Rubio would stand to pick up only about a third of Jeb’s supporters—gains that would be partially offset by Trump and Cruz’s own pickups from Bush. And keep in mind that we’re not divvying up a massive base here; Jeb had only 4 percent support in the NBC poll, roughly in line with what he’d been averaging. (Carson, meanwhile, had the support of 8 percent of the respondents, and his supporters were more likely to name Trump or Cruz as their plan B.)

This isn’t a new phenomenon. A Fox News poll taken at the end of July, for example, found that Bush’s fans were more likely to name Trump as their second choice than anyone else in the field—and vice versa. In a world where a not insignificant slice of the electorate can imagine themselves switching their allegiances between a political scion who plays by the traditional rules and a first-time candidate who refuses to bow to even basic decorum, it stands to reason that Republican voters can’t be so neatly divided along the establishment/anti-establishment axis that the political press corps (myself included) likes to use to sort the candidates.

Rubio, meanwhile, was always the outlier in the party-approved foursome that emerged at the end of last year. The Florida senator is far more conservative than Bush, Kasich, and Christie, and has far less political experience than the three governors. If you’re a voter who liked Bush or Christie for their record, it’ll be easy to find something to like about Kasich but it’s unclear what you would find inherently attractive about Rubio. Marco’s biggest selling point is the perception that he’s best suited to win the general election—a category he seems to be winning by losing on the topics that have so far defined the Republican primary. Yes, Rubio stands to benefit more than anyone else in the race by Bush’s exit, but it’s far from certain that he’ll benefit enough—especially if it remains a three-man race for the foreseeable future.

That said, Rubio really does have good reason to cheer his former mentor’s departure. Republican governors and lawmakers who had remained on the sidelines out of respect for the Bush family are now free to back Rubio, as many are now doing. Those endorsements, in turn, could serve as a signal to some of the now candidate-less voters about who they should choose next. And while Rubio won’t pick up all of Bush’s votes, he will likely pick up many of his donors—and, at the moment, it’s the money that may be the more important of the two. Over the weekend, Rubio reported having only $5 million on hand to start the month, far less than the $13.6 million in Cruz’s campaign bank account and Trump’s effectively limitless resources. With multicontest dates on the horizon, Rubio will need an influx of cash to stay competitive with his two main rivals. And even if a few of Bush’s deep-pocketed friends decide to stay on the sidelines, the simple fact that Jeb is no longer running means that his super PAC will no longer be spending tens of millions of dollars trying to tear Rubio down. He’ll still need to fend off Kasich’s attacks from the center, but for the first time Rubio will be able to focus most of his attention on the fire coming from his right.

All that may be enough to convince Republican voters that Rubio’s not just their best choice, but their only one. Right now, though, too many Republican voters still believe they have other options.

Read more of Slate’s coverage of the GOP primary.