WASHINGTON -- GOP presidential candidate Jon Huntsman is vying to be the voice of moderation in the Republican presidential race, and in the process on Sunday slammed his opponents and even a question at a Fox News debate in which he participated. 

Saying the U.S. is a "center-right" country politically, the former Utah governor and President Obama's ambassador to China, Huntsman said the public is "crying out for a sensible middle ground."

"We've had so much hope and hype in politics the last little while. We've found ourselves at the extreme ends of the political spectrum. And people are crying out for us to get back to some level of sensibility," he told ABC's "This Week."

Ticking off criticisms, Huntsman said Obama is too liberal and the Republican candidates are too far right and have "zero substance." He described former Massachusetts Gov. Mitt Romney as a flip-flopper, who previously opposed a flat tax. 

"If we were to talk about his inconsistencies and the changes on various issues, we'd be here all afternoon. But if he's in favor of a flat tax now where he wasn't before, at least he's moving in the right direction," he said.

Huntsman, who's lagging in national polls, saved his harshest criticism in a television interview for two of the candidates who are at the top of the 2012 pack -- Texas Gov. Rick Perry and Minnesota Rep. Michele Bachmann.

Huntsman slammed Perry for expressing skepticism about manmade global warming and for criticizing the nation's central banker.

"Well, I don't know if that's pre-secession Texas or post-secession Texas, but in any event, I'm not sure that the average voter out there is going to hear that treasonous remark and say that sounds like a presidential candidate, that sounds like someone who is serious on the issues," Huntsman said in interview, aired Sunday on ABC's "This Week."

Huntsman also ridiculed Bachmann's claims that she could bring gasoline prices below $2 if elected president. "I just don't know what world that comment would come from. ... That is completely unrealistic. And, again, it's talking about things that, you know, may pander to a particular group or sound good at the time, but it just simply is not founded in reality."

Asked about why he agreed with the candidates when they were asked to say whether they supported a 10-1 tax cuts to spending increase, Huntsman suggested the problem was with the question, not his answer. 

"It was a nonsense question. And the fact that you can even ask a question that is that important with such profound implications for the United States, to answer by show of a raised hand, I mean, come on," he said. "You know, what have debates gotten to, in terms of how we discuss the truly important issues of the day?"

Huntsman got backing on that view from former George W. Bush senior adviser Karl Rove, who earlier criticized Perry on his remarks about the Federal Reserve. Rove then told "Fox News Sunday" that he too thought the question was too easy

"With due respect to your question, that was a question that had a predictable answer to it, and that kind of a thing when you're asking people to raise their hand and not offering them a chance to get a nuance answer, you're going to get raising hands," he said.

Huntsman, who is garnering around 2 percent in public opinion polls of the candidates, spoke optimistically about his chances in 2012, saying he would do well in early voting New Hampshire and South Carolina and "then we're going to bring it home in Florida."

"I'm confident we're getting there. But I'm even more confident that the message that we bring to this race, that of a center-right message for a center-right country that is looking for common-sense solutions and a leader who's actually been there and done that in the marketplace and can apply those same principles now to a nation that so desperately needs it," he said.

He said voters aren't yet paying close attention to the race. "I like exactly where we are. Stay tuned."

The Associated Press contributed to this report.