It’s not just Herman Cain.

As you may have heard, Cain, the longshot GOP presidential candidate, told Think Progress last week that if elected president, he would not consider any federal appointments of Muslims. Cain explained: “There is this creeping attempt, there is this attempt to gradually ease Sharia law and the Muslim faith into our government.”

This wasn’t Cain simply being entrapped by a wily questioner. Cain had expressed similar anti-Muslim sentiments in an interview with Christianity Today a few days earlier.

Appealing to your base’s id is a tried-and-true method dark horse candidates use to garner attention. This is why Donald Trump has spent the last couple of weeks expressing doubts about the president’s birthplace. But frank expressions of anti-Muslim animus are also coming from mainstream GOP contenders.

As Steve Benen points out, former Massachusetts Governor Mitt Romney actually said in 2007 he would not appoint Muslims to his cabinet. So it’s unclear if there’s any daylight to speak of between Cain and Romney when it comes to disdain for Article VI of the Constitution of the United States, even as (or perhaps because) Romney himself faces prejudice regarding his own faith. Meanwhile, Minnesota Governor Tim Pawlenty last week frantically and implausibly denied any association with a program that helped Muslims in Minnesota purchase mortgages — illustrating how politically perilous it may be for any aspiring Republican presidential candidate to be seen as tolerant of Muslims.

The apparent need to signal intolerance towards Muslims may prove to be an important feature of the 2012 campaign — during the primary and beyond. After all, Republicans are more likely to have negative views towards Muslims. But in addition to this, as political scientists Michael Tesler and David Sears wrote in a 2010 study, feelings about Muslims are actually a strong predictor about feelings about Obama. They found that “general election vote choice in 2008 was more heavily influenced by feelings about Muslims than it was in either 2004 voting or in McCain-Clinton trial heats.”

People with positive opinions of Muslims are actually less likely to be birthers. So it doesn’t seem like a coincidence that according to the Tesler and Sears study “only 21 percent of Fox viewers said that Obama was American-born.” Viewers of Fox News are also more likely to have negative views of Muslims.

All of this makes it fair to ask whether some of this anti-Muslim sentiment reflects opposition to Obama generally, and whether dislike for Obama, combined with the mistaken belief that he is a Muslim, has actually contributed to the mainstreaming of Islamophobic conspiracy theories on the right. If so, pandering to Islamophobia may be an easy way for a Republican candidate to communicate his or political instincts to the base, and thus may become an enduring and unalterable feature of the 2012 presidential race that will only intensify as the campaign develops.

UPDATE, 12:31 p.m.: I neglected to mention that Romney claimed reports of his 2007 remarks were not accurate. It’ll be interesting to see what role he’ll play here going forward, and whether or not he’ll fight or acquiesce to Islamophobic pressure from the right.