GOP's Huckabee: I'm still in, despite Walker calls

In this for the' long haul': Mike Huckabee

Republican presidential candidate Mike Huckabee said Tuesday he's in the race "for the long haul," despite Scott Walker's call for other candidates to follow his lead and drop out.

Walker—unable to arrest his sliding poll numbers after the second GOP debate—ended his White House bid Monday evening. He called on other GOP hopefuls with lower poll numbers to do the same "so the voters can focus on a limited number of candidates who can offer a positive conservative alternative to the current front-runner," taking a shot at Donald Trump without mentioning him by name.

In the RealClear Politics polling aggregator, Trump still leads the crowded field by a wide margin with 28.5 percent support. Huckabee comes in seventh with 4.8 percent.

After Walker's announcement, Jeb Bush rejected the notion that he might leave the race. The former Florida governor has 7.8 percent support and is in third place, according to RealClear Politics.

Former Texas Gov. Rick Perry dropped out before last week's CNN debate.

How my FairTax plan works: Mike Huckabee

Huckabee told CNBC's "Squawk Box" on Tuesday that his campaign has been handicapped by the media giving candidates such as Trump much more coverage.

"For example ... during the period of August 24 to September 4, Donald Trump got 580 minutes of television time on CNN. I got six seconds, cumulatively in two weeks. I got next to the least amount of time. Governor Walker was the only one with less time," said Huckabee, a former governor of Arkansas. "You put that much helium in somebody's balloon and it's going to float."

"I bring a pretty substantial record to the stage, but nobody is going to hear about it. They're going to ask me some question about my religious beliefs," said Huckabee, a former Baptist minister.

He also defended his "fair tax" proposal to eliminate the federal tax code and replace it with a national sales tax expect on necessities.

"People at the bottom third of the economy end up being better off than anybody by about 14 percent," he said. "The middle third, they do about 7 percent or 8 percent better. And the top still do 4 percent or 5 percent better."