Republican presidential candidate Mike Huckabee speaks with moderators at an economic forum Jan. 9 in Columbia, S.C. (Sean Rayford/AP)

CHARLESTON, S.C. — Shortly before a closed-door "Huckabee Huddle" with local pastors, former Arkansas governor  Mike Huckabee weighed in on the question of the week. Yes: He too had questions about whether Sen. Ted Cruz (R-Tex.), born in Canada to a Cuban father and American mother, was eligible for the presidency. It certainly seemed to pose a problem.

"When it first surfaced, I didn't think it did," Huckabee said. "But after now reading a number of very thoughtful pieces by constitutional experts, yeah, I think it should give everybody a little concern. It's an issue that's got to be dealt with. There was one article from Lawrence Tribe, and there was another from a professor who wrote in The Washington Post, and it was very compelling argument. It was not a political argument. This person gave very serious reasons as to why this was a serious question."

In a few words, Huckabee became at least the fourth rival to Cruz to ask whether his eligibility could be questioned. Carly Fiorina cited "legal scholars" who had judged the issue "legitimate." Sen. Rand Paul (R-Ky.), who had once brushed off the question, suddenly called it a potential problem. And then there was Donald Trump, whose predictable obsession with the topic seemed to finally end the mutual admiration pact between Cruz and himself.

That would have been bad enough, had Republicans as eminent as RNC Chairman Reince Priebus, Sen. John McCain (R-Ariz.) and Gov. Terry Branstad (R-Iowa) refused to simply call Cruz eligible, or call the question ridiculous. Today, as Cruz campaigns in South Carolina, his supporters see the entire eligibility debate as an obvious bad faith ploy.

Some of the Republican presidential candidates are going after Sen. Ted Cruz (R-Tex.), saying his birthplace could count against him in a presidential election. Here are the facts. (Sarah Parnass/The Washington Post)

"I think it's pretty simple," said a frustrated Rep. Paul Gosar (R-Ariz.), who endorsed Cruz this week. "You're either a natural born citizen or a naturalized citizen. He's not naturalized, so he's natural born. It's pretty darn simple: John McCain is a hypocrite for talking about this."

McCain, who was born in the Panama Canal Zone to a military family, has been cited by Cruz as a precedent for the eligibility of people born outside the United States. Cruz, who proudly tells conservative audiences of his Senate floor debates with McCain, also quotes him occasionally and says they have become friends. Indeed, McCain used an interview before the State of the Union to walk back the implications of his eligibility question.

But to some conservatives, like Rep. Mark Sanford (R-S.C.), the whole debate was a transparent effort to hurt Cruz.

"Isn't it obvious? They don't like him," said Sanford, who is campaigning with Cruz (but not endorsing him) tonight in Rochester, S.C. "Apparently Branstad's son works for a PAC that disagrees with Cruz on ethanol. McCain: It's been pretty well documented that he's not a Cruz fan. This seems to me like one of those cases of one plus one equaling two."