In the end, whoever wins the GOP presidential nominating contest will have to take on Barack Obama, who’s looking more and more vulnerable.

But for now, the fight is over the Republican Party’s vision for the country – and perhaps just as critical, for itself. At the moment, that intramural struggle is best seen in the contrasts between Jon Huntsman and Rick Perry.

Aside from the fact that they’ve both been governor of a western state, they have very little in common. Perry is a tea party favorite; Huntsman is more moderate in tone and substance. Perry’s family was not wealthy; Huntsman’s father is a billionaire. Perry is all-Texan; Huntsman has a world view shaped by years abroad as a Mormon missionary and ambassador to Asian nations under presidents George H. W. Bush (Singapore) and Obama (China).

It’s hard to imagine Huntsman whipping out a pistol with a laser sight and blasting a coyote, as Perry once did while jogging. Yet Huntsman has been taking rhetorical potshots at his outspoken Texas rival lately, a recognition that the former Utah governor needs to jazz up his campaign if he is to join the top-tier candidates.

On ABC’s “This Week” Sunday, Huntsman criticized Perry’s recent comments on global climate change (“a scientific theory that has not been proven”) and evolution (“a theory that’s out there”).

“When we take a position that isn’t willing to embrace evolution, when we take a position that basically runs counter to what 98 of 100 climate scientists have said, what the National Academy of Science has said about what is causing climate change and man’s contribution to it, I think we find ourselves on the wrong side of science, and, therefore, in a losing position,” Huntsman said.

Huntsman also took aim at Michele Bachmann, another strong candidate and tea party favorite, for claiming in South Carolina last week that her energy policy would bring gasoline prices back down below $2 a gallon – a promise Huntsman called “completely unrealistic.”

“We live in the real world. It’s grounded in reality. And gas prices just aren’t going to rebound like that,” he said. “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.”

Aiming more broadly, Huntsman blasted all his GOP opponents for refusing to support the recent congressional compromise on raising the debt ceiling and avoiding default. (He was the only one to do so.)

"I wouldn't necessarily trust any of my opponents right now … when every single one of them would have allowed this country to default," Huntsman said on ABC. "So I have to say that there was zero leadership on display in terms of my opponents."

Huntsman isn’t the only one targeting Perry, who jumped into the race a week ago and quickly became the focus of attention and support.

Republican mastermind Karl Rove said Perry’s charge regarding Fed chairman Ben Bernanke (potentially “treasonous”) was “over the top” and “not presidential.” (There’s a long history of competition and dispute between the Perry and Bush camps in Texas, of which Rove is a key figure, but that needs much more space to explain.)

Meanwhile, now that Perry is officially in the race, his political record is coming under greater scrutiny.

“A review of Mr. Perry’s years in office reveals that one of his most potent fund-raising tools is the very government he heads,” the New York Times reported Saturday.

“Over three terms in office, Mr. Perry’s administration has doled out grants, tax breaks, contracts and appointments to hundreds of his most generous supporters and their businesses,” the Times reported. “And they have helped Mr. Perry raise more money than any politician in Texas history, donations that have periodically raised eyebrows but, thanks to loose campaign finance laws and a business-friendly political culture dominated in recent years by Republicans, have only fueled Mr. Perry’s ascent.”

Other analysts note that Texas – governed by Perry for the past ten years – has less-than-sterling rankings among states on high school graduation, child poverty, and relatively regressive tax laws that “redistribute income away from ordinary families and towards the richest Texans,” as the Institute on Taxation and Economic Policy puts it.

All potential debating points for Huntsman and the other Republicans hoping to deflect Perry on the way to ousting Obama.