Jeb Bush: Rubio is a good guy, but I'm a leader

Former Florida Gov. Jeb Bush said Monday he intends to still be campaigning when his home state holds elections next month.

Once a frontrunner, Bush has fallen to the middle of the pack in the Republican contest for the presidential nomination. In addition to trailing billionaire Donald Trump and Sen. Ted Cruz of Texas, he has recently slipped behind fellow Floridian Sen. Marco Rubio.

"I'm totally confident I'll be campaigning in Florida, and I'm confident I'll do really well there with the best organization," Bush said in an interview on CNBC's "Squawk on the Street."

Florida holds its primary on March 15 and is one of a handful of winner-take-all primaries, which award all the state's delegates to the first-place finisher.

Bush noted he has the support of three statewide elected officials, a majority of the congressional delegation, and Florida's past speakers of the House, with the exception of Rubio.

"They're supporting me. It's not because they don't think Marco Rubio is a good guy. He is. It's that I'm a leader," Bush said.

Support appeared to be coalescing around Rubio as the Republican establishment's answer to Trump and Cruz after the junior Florida senator's strong showing in the Iowa caucuses last week. But some say his performance during Saturday night's debate has sapped support from his campaign.

In a widely aired exchange during Saturday's debate, New Jersey Gov. Chris Christie attacked Rubio, saying he was not prepared to be president and had few accomplishments to speak of.

"I think the whole attitude of the Republicans toward the race changed a lot this weekend," long-time GOP campaign adviser Vin Weber, a Bush supporter, told CNBC's "Squawk Box." on Monday "People are hitting the brakes, saying let's not rush to judgment. Let's get this right. I think there's a greater emphasis on experience."

Weber, said he believes Rubio's loss is a gain for Bush and Ohio Gov. John Kasich.

Still, Rubio has the support of 17 percent of likely Republican voters in New Hampshire, putting him behind Trump, who commands 30 percent support, according to a NBC News/Wall Street Journal poll conducted after the Iowa caucuses.

Cruz trails just behind Rubio with 15 percent, followed by Kasich with 10 percent and Bush with 9 percent.

Bush told CNBC he believes New Hampshire voters will be focused on which candidates have sound policy when they turn up to vote in the first-in-the-nation primary on Tuesday. Bush has largely stood on his plans to expand the U.S. economy by 4 percent or more through tax and regulatory reform.

Asked whether he thought a surprise third place finish would put him back into the running, he said, "I've got a list of obituaries that have been written about me. Third means I'm alive, I guess, and that's beating expectations."

As for Trump, with whom Bush has developed an acrimonious rivalry punctuated with personal attacks, he said Trump "isn't a serious person."

"He's fantastic at playing the role of a candidate, but as president of the United States you can't disparage people the way he does," he said. "You can't insult people the way he does, and you've got to have an economic policy that's grounded in solid, conservative principles, and he doesn't."