There’s nothing revelatory here if you’ve followed the campaign but it’s striking to see people in Cruz’s orbit talking about endgame on the eve of the big vote. Ten days ago, South Carolina was supposed to be the rubber match between Trump and Cruz, the winners in New Hampshire and Iowa. Ten days later, there’s more suspense over whether Cruz will hold off Rubio for second than whether he’ll catch Trump for first. Cruz’s strategy at the start of the month was straightforward: Clean up among evangelicals in Iowa and win the caucuses (check), perform respectably in New Hampshire while hoping that Trump crushes Rubio (check), then show the RINO from Manhattan who’s boss on February 20th when the south and its many Christian conservative voters start voting in Carolina. Once SC is won and the Trump balloon is punctured, Cruz surfs the momentum into the SEC primary on March 1st and cleans up, capped by a clear majority win in his home state of Texas that delivers all of that state’s delegates to him. A demoralized Trump likely quits at that point. Rubio soldiers on, but the early delegate lead piled up by Cruz plus the momentum of his string of victories plus the many millions of evangelicals who haven’t voted in recent elections but who’d supposedly be turning out for Cruz this year would hold off Rubio and deliver him the nomination.

Something went wrong, and it went wrong in the place Cruz least expected to encounter trouble — the south, in a famously evangelical state. Polls this week show Trump leading Cruz among evangelicals both in SC and nationally, which is partly an artifact of Rubio gobbling up some of Cruz’s voters but which wasn’t supposed to happen even in a multi-candidate field. Cruz may well finish second tomorrow night, but if he’s not competitive with Trump in SC there’s no good reason to think he’ll be competitive in the SEC primary. And if he isn’t, if it’s Trump rather than Cruz who piles up a delegate lead on March 1st, how does Cruz climb back into the lead as bluer states, which would presumably favor more moderate candidates like Trump and Rubio, get ready to vote? Cruz’s allies claim that he’s aiming to take 60 percent of the delegates in the SEC primary, but given that those states award delegates proportionally that’d be hard to do even if Trump and now Rubio weren’t looking as tough as they are. Lotta bad vibes in Cruzworld all of a sudden:

“If they’re pretty far back from Trump and they can’t get southern conservative evangelicals in South Carolina, I do think they’re probably going to have a hard time elsewhere,” said Erick Erickson, a conservative writer in touch with Cruz’s team. “I sense a real fear from people that if Trump blows everybody out of the water in South Carolina, that he is suddenly unstoppable.”…

Several people close to the campaign concede that losing South Carolina by double digits would spell serious trouble for Super Tuesday. If it’s a tighter loss, some say, it would validate the theory that Trump was susceptible to their attacks and encourage more.

“Everybody is watching: Can support be stripped from Donald Trump?” one pro-Cruz fundraiser asked, predicting that if Trump only earns between 25% and 30%, it will “unleash” a new wave of anti-Trump money. “Then people will realize Trump can be beaten in a lot of the March 1 states.”

“But if Trump gets 38 or 40 — and Cruz is second with 22 or something like that — it’s going to be very ominous,” the fundraiser added…

Cruz surrogate Jack Kingston, a former congressman from just over the border in Georgia, went so far as to tell reporters Thursday that Cruz “shouldn’t even be viable” in South Carolina, quite the departure from a state that Cruz’s team once saw as winnable.

Saying that Cruz shouldn’t be viable in South Carolina is only slightly less absurd than saying Mitt Romney shouldn’t be viable in Utah. In fact, that’s the most striking thing about Cruz’s operation this week — and I say this as someone who prefers him to Rubio (and vastly prefers him to Trump): They do increasingly seem desperate in their spin, which may be the surest sign that Rubio really is gaining on Cruz in the polls. One example was that odd, lengthy Cruz press conference the other day which started off as a rebuke to Trump for his phony defamation threat and then went on and on about Trump’s and Rubio’s lies. Another is Team Cruz making a play among social conservatives by attacking Rubio for hiring an advisor who supported the plaintiffs in the Supreme Court’s gay marriage case — even though, as it turns out, Cruz has advisors who held the same position. The latest this afternoon is a report of a robocall by a pro-Cruz group attacking Trump and Rubio ally Nikki Haley for opposing flying the Confederate flag on the statehouse grounds. The complexion of those attacks might feel less “kitchen sink” if Cruz were leading the polls instead of trailing Trump badly, but we are where we are. (Where, by the way, is Cruz’s attack today on Trump for saying he likes the ObamaCare mandate?) If Cruz still thought South Carolina was about to deliver him a win on the strength of the Christian vote, presumably Team Cruz would be spending every bit of its messaging power at this point on hammering Trump for “New York values,” not all of this.

Dave Wasserman of FiveThirtyEight looks ahead and sees some rough delegate math for Cruz after March 15th, when states are suddenly free to choose winner-take-all:

An examination of the GOP delegate landscape shows that in states where evangelical Protestants are at least 30 percent of the population, just 22 percent of delegates will be awarded on a winner-take-all basis,1 compared to 47 percent of delegates in other states…

This delegate allocation matrix puts Cruz’s campaign at a serious disadvantage. For example, if Cruz wins the primary in his home state of Texas by one vote, he’ll probably win a handful more delegates than his nearest competitor. By contrast, if Marco Rubio or Trump win Florida by one vote, either would win a whopping 99 more delegates than his nearest competitor.

If Rubio really does surge into second tomorrow night and is competitive with Cruz for delegates in the SEC primary on March 1, Cruz will face a very tough choice. Does he keep going, knowing that he no longer has a realistic path to winning a majority of delegates but might be able to hold Trump and Rubio under a majority too, which would mean a brokered convention? Or does he pull the plug and get behind Rubio in order to try to unite conservatives against Trump? Or, third option, does he get behind Trump and try to unite populists against Rubio? That wouldn’t sit well with lots of Cruz’s conservative fans, but then backing Rubio wouldn’t sit well with his populist ones. By forging on, he could pile up enough delegates to make him a kingmaker at a convention divided between Trump and Rubio, but that’s a dangerous play when Trump is already a serious threat to go all the way. If Cruz finds Trump as politically objectionable as he’s been claiming lately, he’ll have to think carefully about how much risk of a Trump nomination he’s willing to absorb in the name of maximizing his own self-interest. Frankly, I fear Ben Shapiro is right: The fact that Cruz couldn’t seal the deal in SC and has allowed Rubio back into the race, guaranteeing a three-way split instead of a two-man contest for the nomination, may have all but clinched the nomination for Trump. I’d go as far as to say that if Trump blows out Cruz tomorrow night and Bush shocks everyone by finishing a surprisingly close fourth behind Rubio, the race is effectively over. And since that’s the worst possible outcome, that’s probably what’ll happen.