Although Cruz is campaigning aggressively, his advisers are concerned about the barrage and are now scrambling to reset expectations for him here. They insisted Monday that the senator from Texas always has been the “underdog” in Iowa and argued that a second-place finish to Donald Trump should be interpreted as a mark of grit and would catapult him onward in the nominating contest.

“I can’t guarantee we’ll win,” Cruz told a group of pastors Monday at a private meeting in Cedar Rapids. “I don’t know that. That’s out of my hands. I believe we have a path to victory.”

Still, a loss in Iowa — the state where Cruz has campaigned the most and where the GOP’s deeply conservative base seems a natural fit — would call into question the depth of his coalition. Also at stake is the credibility of his vaunted data and field operation, which in Iowa is believed to be more sophisticated than any other Republican’s…

“Welcome to the big time, baby,” said Tim Albrecht, a former Branstad aide who is advising former Florida governor Jeb Bush’s campaign. “You put your head out there, it’s going to get lopped off. That’s exactly what’s happening.”