Tom Smart, Deseret News
Jon Huntsman walks into a fundraiser Aristo's restaurant on 224 South 1300 East Tuesday, Aug. 16, 2011, in Salt Lake City, Utah.

WASHINGTON — Jon M. Huntsman Jr., a former Utah governor who has been stuck in the second tier of candidates for the Republican presidential nomination, took an assertive new tone during a televised interview Sunday, saying that recent remarks by two of his major rivals were "extreme" and "unrealistic."

He was referring, respectively, to two of the most conservative Republican candidates for president — Gov. Rick Perry of Texas and Rep. Michele Bachmann of Minnesota — both of whom have overshadowed him in surveys of Republican voters.

Huntsman singled out two areas of commentary by Perry that have drawn particular criticism: Perry's skepticism about the human causes of global warming as an unproven theory, and his suggestion that actions by Ben S. Bernanke, the Federal Reserve chairman, to give the economy a boost might be "treasonous."

In his appearance on the ABC News program "This Week," Huntsman warned against the Republican Party becoming "the anti-science party." He added, "I think when you find yourself at an extreme end of the Republican Party, you make yourself unelectable."

Huntsman also scoffed at Bachmann's suggestion that, if elected president, she would help bring the price of gasoline below $2 a gallon.

"I just don't know what world that comment would come from," Huntsman said. "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."

Huntsman, who served as the ambassador to China under President Barack Obama before quitting that post this year to pursue the presidency, has tried to stake out a middle ground in a contest where the loudest voices have come from what he referred to on Sunday as "the fringes."

Huntsman insisted that the American public was "crying out for a sensible middle ground." He described the United States as a center-right country and said that was precisely where he stood.

Huntsman fared poorly in the Ames Straw Poll on Aug. 13 in Iowa, a state to which he had devoted little attention. He received less than 1 percent of the vote; Bachmann won with 29 percent.