Donald Trump, Ben Carson Lead GOP Polls

Trump offered previews of those attacks in the days leading up to the debate.

But the shift could cause Trump to change his tactics at the debate sponsored by CNBC.

But neither party's a clear victor on the issue - 15 percent say they trust both equally and 30 percent say they trust neither party. But in Iowa, Trump expressed befuddlement.

"Trump is going to have to colour inside the lines a bit more than he's used to because people are starting to ask whether he's safe to be president, " said Jessica Levinson, who teaches political ethics at Loyola Law School in Los Angeles.

During rallies in Florida over the weekend and in New Hampshire on Monday, Trump referred to reporters as scum and liars who were out to get his campaign.

While Trump's taunts have rattled opponents, he has yet to land on an insult for Carson, who is the most well-liked GOP contender.

At times, they seemed desperate for attention. He has not been able to shake the "low energy" tag Mr. Trump slapped on him and donors are increasingly nervous. "Right, right. Don't go after the nice guy". He even took a vague shot at Carson's faith, suggesting that Seventh-day Adventists were less mainstream than Presbyterians like himself.

Carson, who has made several controversial comments about homosexuality and Muslims, said he has no plans to change his public rhetoric.

Clearly speaking of Carson, Kasich said, "We got one candidate that says we ought to abolish Medicaid and Medicare". And you know what a disaster that is. Now, I'm sure one day he'll take it back. "I mean, he's the strongest man for the job, I feel, then he has to do what he has to do".

Carson, a soft-spoken retired neurosurgeon, stuck to his low-key style and sought to explain his vague tax policy, which he has compared to tithing, in which families donate the same portion of their income to their church regardless of how much they make. "We're all in this together".

"I talked to economic advisors who have served presidents of both parties", he said. "I think that's the Number 1 threat near-term threat to Trump". Also, we can stimulate, that's going to be the real growth engine: "Stimulate the economy". 

A joke, but perhaps one with more than a grain of truth.

Marco Rubio shined on the debate stage Wednesday night -- and the timing couldn't have been better. That's not new. But there was something different this time.

Preference polls are a far-from-perfect way to predict election outcomes, especially with voters still three months away from casting ballots in the first-to-vote Iowa caucuses.

Q: Ben Carson is not a forceful debater, but he's suddenly on top of the polls. The poll found that 51 percent of conservatives view Cruz favorably or somewhat favorably-so it makes a few sense Cruz figures if Trump and Carson burn out, those votes will skip Rubio and Bush and fall to him.

GONYEA: And he pointed out his big lead in South Carolina, another early voting state. But in Iowa - Iowa - Ben Carson is now on top. Known for his reserved and calm demeanor, the candidate has repeatedly said he has no interest in becoming an attack dog.

Asked about his biggest weakness with the first question of the debate, Kasich dismissed it and began a tirade about the seriousness - or lack thereof - in the Republican campaign. But the evangelicals left me down a little bit this last month.

GONYEA: To underscore his Christianity, campaign handouts last night included a photo of Trump at his 1959 confirmation ceremony. But here comes the tricky part. He largely refrained from personal attacks on his rivals, which has been a signature of his campaign, even taking a light touch with Carson, who has overtaken him in recent Iowa polls.