The results of the South Carolina primary helped the Republican Party winnow the field, effectively, to a three-candidate race. But there’s a long way to go for the GOP to get to two. Donald Trump retains an edge until that happens.

After Saturday’s win, Trump has now easily pulled off the New Hampshire–South Carolina double. Modern Republican electoral history is black-and-white here: the candidate who does this wins the nomination. Modern Republican electoral history also has a small sample size, though, and there’s still a scenario in which Trump goes down: if he’s faced with a one-on-one contest against either Sen. Marco Rubio or Sen. Ted Cruz. The problem for the anti-Trump majority is how to get from that three-candidate race, which South Carolina’s results reinforced is the true dynamic of the contest, to a two-person race.

Rubio and Cruz essentially tied for second place in South Carolina with support in the low-20s, compared to Trump’s more than 32 percent of the vote. Much like after Rubio’s third-place finish to Cruz and Trump in Iowa earlier this month, the Rubio-industrial complex is touting this double-digit defeat as a dramatic victory for the Florida senator. If he finishes in second, he will have started the nominating contests with 3-5-2 finishes—far away from his pre-voting “3-2-1” strategy, a path that acknowledged the importance of winning an early state. There’s only one early state left. Though Nevada is a caucus state and we shouldn’t hand it to him just yet, Trump is dominating there in a way that he was not in Iowa, the only completed contest so far that he did not win.

Cruz, meanwhile, has claimed at least one win, but hasn’t been able to translate that into gains elsewhere in the country. Cruz was supposed to be an Iowa winner with the resources to build from there, unlike recent winners Mike Huckabee and Rick Santorum. It’s not promising for him that he’s going to finish somewhere in the low-20s in South Carolina after what amounted to a bye week in New Hampshire. It’s also hard to see where Cruz gets his wins now, with the notable exception of Texas. And he needs his wins, soon, since his delegate path involves sweeping through the South on March 1 to build up a lead that positions him as the front-runner heading into the big winner-take-all states coming on March 15. The thing is, South Carolina is very much in the South. And Trump crushed him there.

The options for the GOP to find someone who can take Trump one-on-one are now a candidate with the most room to grow, but who hasn’t come close to winning a contest, and another candidate who’s won a contest but is having trouble expanding his support beyond very conservative voters.

On the whole, Rubio has the better argument. With Jeb Bush now officially out of the race and John Kasich living on fumes, he could suck up enough votes (and money) to turn in stronger performances than he has so far. And the calendar will get much more favorable to him—or, at least, much less favorable to Cruz—beginning on March 15.

But even if Cruz does begin trending behind Rubio, what rationale will there be for him to drop out? Most candidates drop out when the money’s gone, and money is not a problem for Cruz. If his support isn’t likely to grow much with Rubio still in the race, neither is it likely to collapse. He can stay around and hope to catch fire at some point along the way—or at least try to secure enough delegates to deny any candidate an outright majority, and take his claim to the convention.

For months one of the leading stories of the election had been the logjam in the “establishment lane” between Rubio, Bush, Kasich, and Chris Christie. This was the story of New Hampshire: four candidates splitting up the large anti-Trump voting bloc and allowing Trump to claim a blowout victory. New Hampshire punted on its duty to select an establishment “winner,” but South Carolina has now resolved that issue.

The “establishment lane” question may now be all but out of the way, but it’s replaced with an even trickier one: Who emerges from the “anti-Trump lane” at this point? The stakes are becoming much higher now than they were in New Hampshire, or even South Carolina. If the Cruz–Rubio collective action problem doesn’t get resolved, Trump will benefit and his prize will be much more than a couple of early primaries. He’ll either win the nomination or head into a convention fight with the delegate lead. In the latter case, wresting the nomination from the delegate leader wouldn’t be a pretty sight.