As the Iowa caucuses near, an influential grass-roots conservative says he believes Mitt Romney’s nomination as the GOP general election candidate is inevitable, and that Romney will ultimately lose to President Obama a year from now.

Erick Erickson, the founder of the RedState blog and a CNN contributor, wrote a lengthy blog post Tuesday that was one part indictment, one part lamentation, as it laid bare, yet again, the deep fissure of mistrust that divides Romney from some conservatives. And at times it read as much as a surrender as a call to arms.

“Mitt Romney is going to be the Republican nominee. And his general election campaign will be an utter disaster for conservatives as he takes the GOP down with him and burns up what it means to be a conservative in the process,” Erickson wrote.

Herman Cain, Erickson wrote, has no shot, because female voters will desert him in the face of the sexual misconduct charges that are eclipsing his campaign.

“He’s down at least 10 points with women in Iowa. He’s falling even further and doesn’t even realize it,” Erickson said. “He’s largely been emboldened by a conservative media that is so used to standing by its men that too few are telling Herman that he is now at the point where he must actually sit and answer questions whether he wants to or not and whether he feels maligned or not and whether I think he should have to or not.”

Similarly, he said, Newt Gingrich’s tangled marital history (three wives) dooms him with the same voting bloc. Rick Perry, he suggested, won’t be able to recover from his record on immigration.

Erickson's blistering critique fell along the same line of attack that Obama’s reelection campaign has adopted: that Romney is inauthentic, that he lacks a “core,” a consistent set of beliefs.

“The man has no core beliefs other than in himself. You want him to be tough? He’ll be tough. You want him to be sensitive? He’ll be sensitive. You want him to be for killing the unborn? He’ll go all in on abortion rights until he wants to run for an office where it is not in his advantage,” he said.

“To beat Barack Obama, a candidate must paint a bold contrast with the Democrats on their policies,” he wrote. ”When Mitt Romney tries, Barack Obama will be able to show that just the other day Mitt Romney held exactly the opposite position as the one he holds today.”

In a sense, Erickson is emblematic of the modern conservative movement, as he has seen his profile as a voice for the rank and file increase along with the rise of the tea party. But that movement, he asserted, is being back by East Coast elites, for whom Romney is the standard-bearer.

“Many of the DC-NYC Republican ‘conservatives’ who support Romney are the same, only coming into contact with regular people when they are served their breakfast by a steward in the first class car on the Acela Express,” he said, engaging in a bit of class warfare himself. “Neither Romney nor the Washington GOP crowd who loves him have very much at all in common with fly over country conservatives who see the GOP and Democrats both as out to lunch tools of K-Street and Wall Street.”

He said that if Romney did indeed lose to Obama, conservatives like him would be criticized for failing to rally to his defense.

“Once he loses, Republican establishment types will blame conservatives for not doing enough for Mitt Romney, never mind that Mitt Romney has never been able to sell himself to more than 25% of the GOP voters,” he wrote.

The state of Erickson's existential despair is apparently such that he now regrets being so dismissive of former Utah Gov. Jon Huntsman Jr., who remains flagging in the polls, well behind Romney and Cain.

james.oliphant@latimes.com