With Texas Sen. Ted Cruz usurping Donald Trump's lead in Iowa polls, the billionaire is launching a new line of attack against his latest threat -- and this time, he's resurrecting a favorite insult usually saved for Democratic presidential candidates and mass shooters.
Speaking with Fox News Sunday, Trump said that he doesn't think Cruz is "qualified" to be president: "When you look at the way he's dealt with the Senate, where he goes in there like a -- you know, frankly, like a bit of a maniac. You never get things done that way."
The billionaire has called several people a "maniac" before -- most notably Vermont Sen. Bernie Sanders and Robert Lewis Dear, the 57-year-old who opened fire at a Planned Parenthood facility in Colorado Springs and killed three people.
"Look, I built a phenomenal business," Trump continued on Fox News. "I'm worth many, many billions of dollars. I have some of the greatest assets anywhere in the world. You can't walk into the Senate and scream and call people liars and not be able to cajole and get along with people. He'll never get anything done. And that's the problem with Ted."
Trump -- who has himself insulted several sitting senators, including fellow Republicans, like Arizona Sen. John McCain, who he has called a "loser" -- also appeared in a CNN interview Sunday priming himself for an upcoming showdown with Cruz.
"He's been so nice to me," Trump said. "I mean, I can say anything, and he said, 'I agree, I agree.' But I think the time will come to an end pretty soon, it sounds like."
On CNN, the real estate mogul also asserted that he had "far better judgment than Ted."
Trump has been ramping up his attacks against Cruz in recent days, coming out with digs about the Texas Republican's religion and his loyalty to the oil industry.
In Des Moines Friday, Trump questioned Cruz's faith, saying that "not a lot of evangelicals come out of Cuba, in all fairness. It's true. Not a lot come out." Cruz, though he was born in Canada, has a Cuban father.
The national GOP front-runner began his offensive on Cruz soon after polls, released earlier this week, showed the senator surging past Trump in the early caucus state of Iowa, where evangelicals make up a large portion of Cruz's support.
A Monmouth University poll out Monday showed Cruz with 24 percent of support among likely Republican caucus-goers in Iowa, 5 points ahead of Trump's 19 percent. And a poll released Saturday shows Trump trailing by even wider margins in Iowa: According to the survey by the Des Moines Register/Bloomberg Politics, Cruz weighed in with 31 percent of likely caucus participant support. Trump only garnered 21 percent.
Cruz, for his part, has largely steered clear of criticizing Trump in public.
In a tweet, the he went so far as to praise the real estate tycoon:
But behind closed doors, he's unleashed his own questions about his rival's character:
"People are looking for who is prepared to be a commander-in-chief," Cruz said at a fundraiser recently, according to audio obtained by the New York Times. During his remarks about Trump and fellow GOP hopeful Ben Carson, the Texas senator asked: "Who understands the threats we face? Who am I comfortable having their finger on the button? Now that's a question of strength, but it's also a question of judgment. And I think that is a question that is a challenging question for both of them."