Much of the reaction to Mitt Romney’s religion speech last week reveals that all too many liberals and conservatives alike oppose a faith that dares to proclaim it holds the truth for all humanity. This opposition runs so deep — especially among the Left — that they will even embrace a religion they distrust to try to stick it to evangelical Christians.

Mitt Romney gave a well-written, thoughtful speech last week. It reflected his intelligence and his beliefs, and it was delivered with eloquence and sincerity. It was well received by everyone except far-left atheists, who blasted it for its generic religious pronouncements.

Too many people embraced it for the wrong reason. Many of the well-wishers were outspoken liberals, who seemed to take a dim view of Mormons and Mormonism. While they don’t know much about Mormonism, they nonetheless saw it as pushing back against evangelicals.

It’s an old political maxim that “the enemy of my enemy is my friend.” While many of these liberals don’t much care for Mormons, they simply despise evangelical Christians. And because they believed that evangelicals rallying to Governor Huckabee were the impetus behind this speech, they decided to side with a speaker whose faith they don’t like to take a jab to those “bigoted” and “intolerant” evangelicals.

Unfortunately, this holds true for many conservative leaders as well. Many of the most respected conservative pundits are none too fond of born-again Christians, either for what they believe or for the political power they sometimes wield.

Mr. Huckabee has every right not to discuss what constitutes a “cult,” or what he thinks of various Mormon doctrines. He’s absolutely correct that such topics do not belong on the presidential campaign trail, and various non-evangelical conservatives who imply he should answer those questions are dead wrong.

The fact is this: Biblical Christianity claims to have the very Word of God in written form, and evangelicals proclaim that without apology. No religion could possibly be more narrow or absolute than one whose author says, “I am the way, the truth and the life.” Those words of Jesus Christ are antithetical to the modern religious trend of relativism. Christianity makes moral claims about how life is to be lived. It proclaims certain things right, and other things wrong.

Against the modern platitudes of tolerance and acceptance, such words seem to be, well, blasphemous. Ironically, the separation of church and state provision of the U.S. Constitution has now become an instrument of religious intolerance.

In America, there are religious differences. That is seen in street preachers handing out religious tracks to share the gospel, just as it is in young Mormon men serving in pairs for their two-year missionary service, going door-to-door trying to win converts to their faith. No one tries to convert someone else unless he believes that other person is of a different faith, and that the person he is talking to should embrace his instead. It need not be un-American to say that there are profound doctrinal differences between Mormons and Protestants or Catholics. A candidate’s religious beliefs may or may not be a factor in a voter’s decision to cast a vote.

Religious liberty does not require us to refrain from discussing such things. Rather, it requires us to respect those who do who are sincere and well meaning, regardless of their religion. For many, it is also a requirement of their faith that they share it with others.

One can be respectful of other faiths, while still believing his own is right. America is pluralistic insofar as everyone’s right to worship in the public square is respected. We are not pluralistic in the sense we have to say religions that flatly contradict our own are equally true with our own.

Too many of both the Right and the Left will have none of that. Having no tolerance for any religion that claims to be the true faith, many talking heads condemn anyone who considers religion a factor in who to vote for, and says that anyone who does is a bigot.

“Bigot” is a nasty word, and is being thrown around all too casually in this discussion. Bigotry is a far cry from respectfully disagreeing with someone’s faith doctrine.

We don’t lynch people in America for being a Methodist, or put them in the back of the bus for being a Pentecostal. Such language is the last thing we need for our public discourse.

All this not only forces people to gingerly tiptoe around their personal faith for fear of being criticized as intolerant, it also forces them to be anti-intellectual. It shuts out the possibility for respectful, vigorous debates to build mutual understanding and find common ground.

This is not about Mormons or evangelicals. Ultimately, it is about respecting people of faith, including those whose faith is so important to them that it influences their vote.

America was, and remains, a religious nation where voters take their values, most likely derived from their religious beliefs, to the voting booths. But, that is truly America’s established tradition of religious liberty.

Mr. Blackwell is a contributing editor of Townhall.com and a senior fellow at both the Family Research Council and the Buckeye Institute.