Saturday night, Rick Santorum attacked Romney; Ron Paul attacked Santorum and Newt Gingrich; Rick Perry attacked everyone — with “the possible exception of Jon Huntsman” (his words). Romney attacked only President Obama; he once again appeared to be above the fray.

So Sunday morning, moderator David Gregory opened the weekend’s second debate by prodding all the candidates to criticize front-runner Romney, who in turn had to descend into the fight. After a series of exchanges in which Gingrich, Santorum and Paul all took on Romney from the right, it was Huntsman’s turn to attack him from some place more reasonable.

”I was criticized last night by Gov. Romney for putting my country first” by serving as Obama’s ambassador to China, Huntsman said.

Still in his no-really-I’m-a-conservative mode, Romney replied: “I think we serve our country first by standing for people who believe in conservative principles and doing everything in our power to promote an agenda that does not include President Obama’s agenda.”

Huntsman responded: “This nation is divided, David, because of attitudes like that.”

Of course, Huntsman hasn’t been immune from pandering to the Republican base this nominating cycle, either. He was trying to justify his greatest political sin among Republicans — deciding to work in the Obama administration — when he went after Romney. And, though he’s brave enough to propose getting rid of some popular tax deductions, he went on Sunday morning to endorse the mathematically challenged Paul Ryan budget plan, which proposes a massive wealth transfer from young to old and a stripped-down federal government — and which still doesn’t forthrightly deal with the budget. So much for righteous truth-telling.

But none of that means that Huntsman was wrong to call out Romney’s revolting claim that his, Huntsman’s, or any American’s “first” duty is to ideology and party.