That was a rough debate for Marco Rubio. He finally got that long-awaited challenge on his previous support for the “Gang of Eight” immigration-law overhaul, which he handled well enough. But any way you look at it, this puts him to the left of the field on the major animating issue of the campaign. He continually took fire from a surging Ted Cruz and a feisty Rand Paul. He spent much of the night on the defensive.

He acquitted himself adequately enough through all that, sure, but what do we really have to support the idea that this is the guy who can prevent Cruz or Donald Trump from capturing the GOP nod? To unite the factions of the party that recoil at the thought of nominating either Trump or Cruz, Rubio may well have needed a much bigger, better night than the one he had Tuesday.

And what Rubio really didn’t need was another establishmentarian like Chris Christie putting points up on the board. Part of the reason Cruz and Trump and Ben Carson have been so successful has been that the moderate vote is divided among so many candidates; the best thing that could’ve happened for the anti-insurgent effort is for a clear alternative to the Cruz/Trump emerging in the very near future, and that sure didn’t happen Tuesday night.

Let’s get the usual caveats out of the way: We’re still a month out from Iowa. Cruz and Trump might yet destroy each other, which would give Rubio more room to rise. Buoyed by a last-minute ad blitz, Jeb Bush could somehow, in theory, come back from the dead. Or maybe, just maybe, we just get to the convention without a clear winner, and the GOP’s muckety-mucks figure out a way to draft an attractively boring guy like Mitch Daniels to run against Hillary Clinton.

But the trend lines should be pretty obvious at this point: Cruz is surging at a good time, maybe a half-step too early; Trump has a legion of diehard fans and solid polling numbers; Rubio, meanwhile, is lagging behind. And if you don’t think Rubio can stop Cruz or Trump, the pickings get awfully slim.

Christie? The guy who spent the last debate at the kids’ table? Sure, I guess, if he can capture New Hampshire and roll into the Southern states with a big win under his belt. But let’s not forget that the Fort Lee traffic jam will continue to haunt him, that he’s squishy on plenty of big issues that are important to the base, that his embrace of President Obama is still ready-made footage for an attack ad, that he’s deeply unpopular in the state he governs and that his temperament hasn’t exactly endeared him to voters outside the Northeast.

But without Christie or Rubio, who is there? Poor old Jeb? Is anyone still holding out hope for a John Kasich surge?

Yes, Rubio has soaked up the Beltway buzz, but no one seems to know what primaries he could actually, you know, win. Right now Rubio is stuck in a distant third in Iowa, some 16 points or so behind Trump in New Hampshire, and fourth in South Carolina. Sure, you say, polls change. As the pollsters themselves remind us, those surveys we get so breathless over are just “snapshots in time.”

Yet with Jeb dead in the water, Kasich unable to gain traction and Christie struggling at the back of the pack, Rubio had what looked like a perfect political moment. Polls indicate he’s the most electable Republican in a race against Clinton, and pundits and the GOP establishment waited for his seemingly inevitable surge.

And waited. And waited.

Now, instead of talk of a boom for Rubio, we increasingly have Republicans wondering how the guy is getting so consistently out-hustled on the ground. “[U]nderneath the buzz, GOP activists in New Hampshire are grumbling that Rubio has fewer staff members and endorsements than most of his main rivals and has made fewer campaign appearances in the state, where voters are accustomed to face-to-face contact with presidential contenders,” The Boston Globe wrote this month. Iowa Republicans, meanwhile, are likewise annoyed that he doesn’t have much of a presence there.

Rubio’s apparent reluctance to really work the trail is all a bit mystifying. He says he’s missing Senate votes because he’s busy campaigning, and then people in New Hampshire and Iowa get miffed that he’s nowhere to be found. You don’t need a lot of money to barnstorm, which is why it’s usually the preferred tactic of candidates like Rubio, who has lagged behind Cruz and Bush in the fundraising race.

TV ads are expensive, so candidates light on cash, the thinking goes, need to really be working voters on the ground. Rubio’s staff, meanwhile, has indicated that they reach enough voters through Fox News and the debates to make up for whatever deficiencies on the trail. So far, his stable but not-great primary polling doesn’t provide a lot of evidence to back up that theory.

As he showed again Tuesday night, Rubio may be the most eloquent speaker in the party—especially on foreign policy. He’s also cut a number of good ads and has a rightly respected communications team. But there’s no reason to think he can continue to run his campaign out of a cable-news greenroom.

It’s possible Rubio still takes off, but the GOP has never nominated a guy who lost both Iowa and New Hampshire, and the latter, where he’s still struggling, is probably a must-win for him. It’s a weird year, sure, but why should we think, in a primary season that’s been dominated by talk of restricting immigration, the guy whose biggest legislative push was for a bipartisan “amnesty” bill will capture the nomination?

So what if the Great Establishment Hope, the insurgent-killer so many of us were waiting for, never emerges? It’s kind of hard to process the Republican nomination coming down to a choice between the Senate’s least-popular showboat and a New York billionaire who’s basically been a liberal all his life. Perhaps that’s why we keep coming back to Rubio and Jeb and maybe now Christie.

But right now it looks like only Cruz and Trump have clear-ish paths to the nomination. Cruz takes Iowa, Trump wins New Hampshire, and then those two duke it out for the Southern states.

Maybe it’s because the other guys just kept committing a series of own goals. Or maybe, when we look back at 2016, we will see it as the year when the GOP transformed into something more akin to the populist, nationalist, anti-immigrant parties we’re seeing in Europe—i.e. the kind of party for which Trump or Cruz would be the obvious standard bearer. Either way, this is starting to look like a two-way race between Trump and Cruz, which means Rubio and company are quickly running out of time to show they can win this thing.