BLOOMFIELD, Iowa — James and Brooks Schooley are raising a young family in this tiny Iowa community. They support Ted Cruz and brought their kids to an old church near the Bloomfield town square to hear the candidate, along with Iowa Rep. Steve King and former Texas Gov. Rick Perry.

The Schooleys like Cruz's faith and his fealty to the Constitution. But their choice is also shaped by their wariness of the Republican front-runner, Donald Trump.

"He's not principled," James Schooley told me, referring to Trump. "He just goes by emotion."

"I feel like he doesn't stick to the Constitution the way Ted Cruz would," added Brooks. "Once you go away from that, then where's your standard? I mean, you can do anything."

Before Brooks finished, the Schooleys' 10 year-old son, until then silently enduring his parents' conversation with a visiting journalist, chimed in. "He can't control his anger," the boy said of Trump in a chirpy voice.

If ever there could be a cute attack ad, this kid could star in it. Everybody laughed.

A couple of hours earlier, at a Cruz stop 25 miles away in Centerville, Jeff and Jessica Lenik offered the adult version of a 10 year-old's assessment of Trump. They like Cruz for his values and positions — faith, Second Amendment, national defense — and they worry about Trump's temperament.

"He's too much of a wild card," Jessica Lenik said of Trump. "I understand his anger, and I get that, and I understand the people behind him. But I think he's too much of a wild card, and without any background in the political arena, that really scares me. Too much of a hothead, I think."

Before Cruz spoke, another Cruz supporter, a woman who didn't want to give her name, worried that Trump just seems a little risky. "I haven't heard anything that makes me truly feel safe with him," she said of the New York businessman.

These conversations took place a few hours before Trump announced that he will not take part in the only Republican presidential debate to be held in Iowa, the Fox News debate Thursday night in Des Moines. Reporters and political insiders argued among themselves whether Trump's move was a disaster or a masterstroke. But however Trump's fight with Fox News executives turns out, among actual Iowa voters, the whole contretemps could confirm and further support an uneasiness about Trump — not that he's wrong about some particular position, not that Iowans doesn't want to make America great again, not that most people don't cheer attacks on political correctness — rather, an uneasiness about the sheer unpredictability of life under a President Trump.

"It's just erratic behavior," said a top Cruz aide in a phone conversation Wednesday morning, after Trump's decision had a night to sink in. "It was emotion-based. It was centered on him. People are a little nervous about electing someone who is so knee-jerk."

Cruz's campaign signs have three C-words on them: "Courageous. Conservative. Consistent." As voting nears, and Iowans make their final decision about which candidate to support, the last of those words is increasingly important. In the end, voters put a lot of store in attributes, like honesty and integrity. And they think a lot about negatives, like unpredictability and uncertainty. Trump's debate gambit confirms the worries voters have about him.

Steve King, hugely popular with Iowa conservatives, has been traveling around the state with Cruz. In a conversation at the church Tuesday, he told me he's hearing more and more worries about Trump. Of course, King is a Cruz endorser, and perhaps he's just in a Cruz bubble, but he also talks to a lot of people of all Republican stripes.

"You can feel it now," King says of a change in voter attitudes. "People are starting to see [Trump's] personality come out, with the relentless Twitter attacks. He can't seem to discipline himself."

King writes notes on his hand. Sometimes it's a random thought he wants to remember. Often, it's a prayer list; it's not unusual for Iowans to come up to him at gatherings and ask for his prayers for an illness, or a financial reversal, or some other problem. King writes their names on his hand and makes sure to offer a prayer before he washes it off.

On Tuesday at the church, King was listening to Cruz and thinking about Trump. He took out a pen and wrote down "Imperial pres." on his hand. When I asked him about it — I've learned to always check King's hand to find out what's on his mind — King said that Barack Obama has already created an imperial presidency, and King worries about a man with a personality like Trump's inheriting the newly-expanded powers of the Oval Office.

"When you think of an imperial presidency handed off to an uber-imperial president that doesn't seem to be restrained," King told me, "then that's an uber-imperial presidency the likes of which we have never seen."

Cruz had a bad run last week. He had had a successful bus tour of Iowa the week before, but when he left to campaign elsewhere, Iowa Republican Gov. Terry Branstad urged voters to reject him. Sarah Palin endorsed Donald Trump. And then Sen. Charles Grassley, the dean of Iowa Republicans, appeared with Trump in an event that led some to assume that Grassley, too, had endorsed Trump. (Grassley hadn't — he's appearing with all the candidates this week, including Cruz — but the impression didn't help.)

Now, however, Cruz seems to have gotten his feet back under him. A new Quinnipiac poll shows him again in a neck-and-neck race with Trump, and Cruz's strategists continue to believe the Cruz ground game is vastly superior to Trump's. They are quick to tick off the numbers: 12,000 Iowa volunteers, 1,800 precinct captains and co-captains, 800 volunteers who have come from out of state and are staying at the always-expanding "Camp Cruz."

But beyond the poll numbers and all those volunteers, what could be helping Cruz most are persistent misgivings about Trump. I heard them from voters at Cruz events. Cruz headquarters hears them in the polls they study nightly. They pay close attention to words voters associate with the two candidates, and they smile when they see "trustworthy" and "honest" topping the list of words associated with Cruz. They're not surprised when they see "strong leader" at the head of the words associated with Trump, but they are also increasingly seeing words like "unpredictable."

Trump's angry exit from the Fox debate could well spur more and more Iowans to come to that conclusion about him. Erratic, seemingly impulsive behavior does not play well with voters. "That is something people do not want to see in a president," said the Cruz aide. "It makes them nervous."