What John McCain said on the Beliefnet program was not quite in line with this orthodoxy. He recognized this almost immediately and took the opportunity to retrench. He resorted to the First Amendment parachute, which is that Congress shall make no law establishing religion, nor denying to anyone the free practice thereof.
Analyses have been written, but not I think pondered by civil servants, that one way to ignore religion is to deprive it of singular meaning. When the Mormons decided in the 19th century that polygamy was required by their religion, prosecutors in various places worked to stamp out the practice. But as time went on, interest in the remaining polygamists died down -- at least until a Mormon, Mitt Romney, declared for president.
It is all very well for Sen. McCain to say that he would have no problem voting for a Muslim for president if he or she was the best candidate. Surely qualifications need to be placed on such effusions of equality. Would it violate the First Amendment for a state to ordain that any Muslim running for public office would have to endorse votes for women? Would have to abjure the commandment that any Muslim defector be executed?
Christianity is supposed to be a way of life, and it was a way of life that Sen. McCain initially spoke of in his Beliefnet interview. Islam is a way of life -- there is nothing in Islam excepting a way of life. We're at about the point when Christians have to admit that we were there when they crucified Our Lord.