At this late date, much of the Republican Party has now settled on the novel idea of stopping Donald Trump. There’s just one problem: Not enough of the party has decided he’s the worst available option.

Despite the intensity of the rhetoric aimed Trump’s way, the most moderate or conventional Republicans who oppose him dislike Ted Cruz even more. The senator was already on the wrong foot for not being enough of a neoconservative to please the party’s foreign-policy holdovers from the Bush years and for clamping down too hard for the establishment’s taste on social issues and immigration. But alone, that stuff wasn’t enough to make him appear even worse than Trump. On top of it all, Cruz is no amateur. In him, the most moderate Republicans see a conservative much more obdurate and manipulative than Trump, someone they won’t be able to negotiate with or outsmart.

But the established leadership should have seen Cruz coming. He had the best path to the nomination before Trump really got going – the clearest logic for scooping up delegates and the best ground game. He didn’t have to bank on capturing the media’s fancy or embodying some party fancy about its future face. He could ride out the campaign’s ups and downs – so well, in fact, that when his theory of the campaign blew up, and Trump romped to the top of the polls, he could still turtle up, make a few jabs and come out of Super Tuesday in a strong-second place position.

Now, even if Cruz can’t win the delegate race outright, he’s enough of an outsider and insurgent figure to make any convention shenanigans or multiple ballots look like the messy end to a messy process, instead of looking like an establishment coup. And a Cruz nomination wouldn’t be a suicide mission: Polls show that despite the stereotypes, he’s actually competitive with Hillary Clinton. With the right VP pick, he’d be even more so.

Unfortunately for Cruz and the rest of the party, these pluses do not erase his minuses that so repel the party’s down-the-middle management. Cruz is the main reason “Operation Stop Trump” is still up in the air.

There also are two secondary reasons, of course: Marco Rubio and John Kasich.

Rubio’s establishment-friendly brand of upbeat conservatism was seen by many in the party as an upgraded, amped-up, 21st-century version of what Jeb Bush was selling. But those people, and the Rubio campaign itself, had to look past the awkward fact that the 21st century already was well underway, and thanks to the Bush legacy, it hasn’t been that great of an era for Republicans. Rubio did his level best to run as a new incarnation of Ronald Reagan, but Trump devilishly revealed it was truer to say that Rubio offered George W. Bush’s third term. Even a lot of voters who don’t want to speak ill of the former president don’t exactly want to run his playbook again.

So Rubio’s campaign has been soured by increasing irritation and hubris, culminating in an insult-laden catfight with Trump over the size of his extremities. Now, the reality is setting in that Rubio’s appeal is limited by the same kind of policy disagreements as Jeb Bush’s. Rubio needs to win his home state of Florida to advance, and right now that seems unlikely. Therefore, he is fracturing the very “Stop Trump” movement he has tried to lead. Some Republicans want him to throw his Flordia support to Cruz; others want him to stay in and lose. Too many people are still holding out hope that keeping Rubio in the mix will somehow prevent Trump or Cruz from prevailing.

In fact, there is really only one important figure who’s against Trump and Cruz but doesn’t want Rubio to drag this out – John Kasich. By far the strangest aspect of this campaign season is Republicans’ failure to rally around Kasich. Although he’s clearly not that many voters’ first choice, he’s a comprehensible conservative who would extend the Bush legacy along a few big-government lines but break with it significantly on others, such as foreign policy – likely a big part of why he still matches up best against Hillary Clinton in head-to-head polls. Kasich is the party’s easy way out of a nasty predicament, which is why he hasn’t folded his campaign. But without an unimaginable shift in public support, he’s really running for vice president at best.

So the Republicans have a stark choice to make. Who is worse: Cruz or Trump? It’s as true in theory as it is in practice that Trump can’t be stopped if he’s not perceived to be the worst available option. If there is a real fracture in the GOP this year, it’ll come down to a failure to forge consensus on that point – or even to horse trade around it.