Iowa Voters Dismiss Trump's Questions on Cruz Citizenship

The issue may even be giving Cruz a boost in Iowa.

One participant said the issue exposes Trump as "unserious,” while another called it a “joke.”

"Just a few months ago, he said his strongest lawyers said it's a settled issue and Cruz is eligible," one participant said. "Now three months later, when Cruz overtakes him in the polls, he says the exact opposite... It's not a serious issue at all."

The focus group expressed admiration for Cruz's handling of the situation, one member specifically calling his “Jump the Shark" tweet response to Trump "awesome."

"He's making a joke of this whole thing because that's what it is," one participant said.

"It's Ted Cruz. Rather than fight it and do something negative, he came back and found something positive and humorous," another added.

But some focus group members said they thought the issue could be legitimate.

"We are nation of laws. And it was important the last time around, with the current president -- if you don't qualify you don't qualify," a participant said, citing questions Trump raised about President Obama's birth, which were proven false.

"There are certain requirements to be president, and I don't care who it is, they have to prove that they are eligible to become president," another participant added.

Trump did get some positive reaction to his new television ad, featuring his stances on banning Muslims from entering the U.S. and building a border wall with Mexico.

"Oh, he won't be happy with that. Only two of you," Luntz said.

One focus group member said that Trump supporters may not translate into actual votes on February 1 in Iowa.

"I'm not convinced his supporters are caucusgoers. You got to give three hours of your night," the member said, as other participants nodded in agreement.

Seven participants in the focus group went so far as saying that if Trump were the GOP nominee, they would not vote for him.

"I know a lot of people who say they will vote for Hillary before they'll vote for Trump. And they're Republicans who say this," one participant said.

"The people who will not vote Republican if he [Trump] is the nominee make me nervous, that is the only hesitation that I have," added a Trump supporter, saying she could "possibly" change her vote from Trump for that reason.

The focus group also acknowledged that Chris Christie, a candidate in the middle of the pack, may be getting a second look in Iowa.

When asked by Luntz if their opinion of Christie has improved over the past 60 to 90 days, almost everybody in the room raised their hands.

"Christie is incredibly articulate. He thinks fast on his feet. He's dialed back his sarcastic outbursts that he was kind of famous for. And he seems really genuine," one participant said.

"I like Rubio. My only concern is he doesn't have years and years of experience," one participant said.

"For me he's Obama II -- someone without experience -- and we suffered the last eight years," another added.