Ted Cruz’s poll-defying victory in the Iowa caucuses Monday night spared the Republican Party the ultimate humiliation of a Donald Trump landslide—not in Iowa, per se, but in the presidential primary writ large. Until this week, nonplussed Republicans were contemplating with dread an increasingly likely scenario in which Trump won Iowa convincingly, reinforced his dominant leads in New Hampshire and South Carolina, and went on to essentially run the table to the nomination. 

Things won’t be quite that straightforward for Trump after all. The early conventional wisdom out of Iowa is that Trump hurt himself by failing to put together a traditional campaign apparatus, that Cruz helped himself by putting together a great one, and that third-place Marco Rubio benefitted from a late burst of pragmatism within the Republican electorate. The results at the very least slow Trump’s juggernaut, and possibly reorient the primary into a real three-way race.

By relegating Trump to second, and even to the waters-edge of third, Cruz and Rubio both widened their paths to the nomination to unknown extent—and at an unknown expense to Trump, whose path narrowed.

Depending upon how the campaigns and Republican voters respond to Monday’s returns, the Trump campaign now faces either a bearish or a bullish outlook. And in many ways, despite the GOP elite’s celebratory mood, the prospect of a quick rebound is less farfetched than a sudden, terminal collapse.

The bullish case for Trump goes something like this. Despite his near-total disinterest in running a traditional Iowa ground game, Trump cobbled together a real and genuinely impressive constituency—at least for Iowa caucuses purposes. More Iowa Republicans voted for Trump last night than have voted for any Republican candidate in history—including Rick Santorum, Mitt Romney, Mike Huckabee, and George W. Bush—except for Ted Cruz, who shattered the record. 

This feat is even more impressive when you factor in the institutional heft behind his competitors’ campaigns. Cruz’s powerful operation was built upon the strength of his close ties to Iowa evangelicals, and to influential local conservatives like Representative Steve King. It’s not unusual for Iowans to support a religious-right tribune in the caucuses (Santorum, Huckabee)—and it’s also not unusual for the winner to ultimately lose the nomination.

Rubio ran a relatively spare campaign, but benefitted both from late but relentless conservative and mainstream media boosterism, and from an equally belated Republican paid-media campaign against Trump. Rubio became the establishment’s de facto candidate in the final week, and it propelled him from a distant third … to a less-distant third.

All of which is to say that caucuses place a premium on traditional campaign infrastructure in a way regular primaries don’t. Iowa is essentially rigged to depress turnout and present barriers to new participants. And yet Trump nearly won anyhow. If that is how Trump and his supporters internalize his Iowa showing, he will perform well in New Hampshire, possibly South Carolina as well, and become a singular force in Republican politics once again.

At the same time, the seeds of Trump’s potential demise are buried just below the surface of this analysis. Barriers or no barriers, Trump underperformed on Monday night. His supporters could prove to be disproportionately flaky in every state. It also may be the case, after all, that a sustained barrage of negative press can harm him. Correlation doesn’t prove causation, but it’s worth considering the possibility that the anti-Trump ads, which flooded the market in the campaign’s final days, contributed to his underwhelming performance.

He will face many more of them in the coming week. If Cruz and Rubio gain ground in New Hampshire, Trump will probably see his lead there narrow before next Tuesday’s primary. If we credit, for the sake of argument, his critics’ favorite but untested hypothesis that his bubble will burst now because it was inflated by the perception of his invincibility, then his own supporters will be discouraged by his second-place finish, and defect to other candidates, or drop out of the electorate altogether.

If these developments transpire, Trump will (finally! at last!) fade from dominance. His campaign will evaporate just as quickly as it materialized, and the race will be transformed into a gloves-off battle between Ted Cruz and the establishment. If he pulls through, though, Republican elites will quickly realize, like an ill-fated resident of Elm Street, that when they woke on Tuesday morning, they brought their nightmare with them.