At an event hosted by Rep. Steve King in Iowa last weekend, the clown car of would-be Republican White House hopefuls quickly put to rest quickly any notion of a "truce" on social issues. And while Newt Gingrich seemed to question whether Islam was a "true religion," former pizza mogul Herman Cain declared that as president he would not appoint a Muslim to his cabinet. But before you brush off Cain's as the ranting of a fringe conservative, it's worth remembering that GOP frontrunner Mitt Romney said pretty much the same thing.

For Republicans now holding show trials into the loyalty of American Muslims and waging a crusade against the mythical threat of Sharia law in the United States, ignoring the Constitution's prohibitions on religious tests for office is just the latest step on a slippery slope. On Saturday, Cain made the jump with both feet. Asked, "Would you be comfortable appointing a Muslim, either in your cabinet or as a federal judge?" Cain responded:

No, I would not. And here's why. There is this creeping attempt, there is this attempt to gradually ease Sharia law and the Muslim faith into our government. It does not belong in our government. This is what happened in Europe. And little by little, to try and be politically correct, they made this little change, they made this little change. And now they've got a social problem that they don't know what to do with hardly.

The question that was asked that "raised some questions" and, as my grandfather said, "I does not care, I feel the way I feel."

Apparently, Mitt Romney feels the same way.

In November 2007, the former Massachusetts Governor said as much to Mansoor Ijaz at a fundraiser in Las Vegas. As Ijaz recounted:

I asked Mr. Romney whether he would consider including qualified Americans of the Islamic faith in his cabinet as advisers on national security matters, given his position that "jihadism" is the principal foreign policy threat facing America today. He answered, "...based on the numbers of American Muslims [as a percentage] in our population, I cannot see that a cabinet position would be justified. But of course, I would imagine that Muslims could serve at lower levels of my administration."

Despite Romney's subsequent denials, Greg Sargent and Steve Benen documented other witnesses and other occasions during which Mitt repeated his No Muslims Need Apply policy.

Given his own membership in a small religious minority, one might expect more openness and tolerance from the Mormon Romney. But the next month, Romney doubled-down on his religious test during his much-hyped "Faith in America" speech. The man who in 2006 declared, "People in this country want a person of faith to lead them as their president" in December 2007 added atheists to his list of those to be excluded from the American community:

"I believe that every faith I have encountered draws its adherents closer to God. And in every faith I have come to know, there are features I wish were in my own: I love the profound ceremony of the Catholic Mass, the approachability of God in the prayers of the Evangelicals, the tenderness of spirit among the Pentecostals, the confident independence of the Lutherans, the ancient traditions of the Jews, unchanged through the ages, and the commitment to frequent prayer of the Muslims."

Just as long as those frequent prayers aren't heard in President Romney's or President Cain's Cabinet Room.

Fifty years after John F. Kennedy took the oath of the office as the nation's first Catholic President, his would-be Republican successors seem determined to erase his message of tolerance delivered to the Southern ministers in 1960:

"For while this year it may be a Catholic against whom the finger of suspicion is pointed, in other years it has been -- and may someday be again -- a Jew, or a Quaker, or a Unitarian, or a Baptist. It was Virginia's harassment of Baptist preachers, for example, that led to Jefferson's statute of religious freedom. Today, I may be the victim, but tomorrow it may be you -- until the whole fabric of our harmonious society is ripped apart at a time of great national peril."

For his part, Rick Santorum welcomes that peril. Earlier this month, the Catholic ex-Senator told , who was not among Saturday's speakers, said he was "frankly appalled" at JFK's declaration that "I believe in an America where the separation of church and state is absolute." As the Boston Globe recorded:

"That was a radical statement," Santorum said, and it did "great damage."

Of course, if Republicans retake the White House in 2012, the real damage to American traditions of religious liberty and diversity will begin.

UPDATE: On Monday, Cain like Romney before him tried to walk back his unconstitutional prohibition against Muslims serving in the highest appointed positions in the land.

(This piece also appears at Perrspectives.)