Is Rick Santorum's Fundamentalist Catholicism at Odds with Protestant Christianity?

Rick Santorum has cast his presidential campaign as a religious crusade and has made no apology for it. Satan is loose in the land, according to Santorum, and he has offered himself as the only man capable of exorcising the demon.

Santorum has surged in the polls among GOP voters precisely because he is so comfortable mixing politics and religion. He presents a stark contrast to Mitt Romney, who seems profoundly reluctant to talk about his Mormonism.

Yet despite putting his religious convictions front and center in his campaign, Santorum hasn't been entirely candid about what those convictions are. He is hiding certain aspects of them in plain sight.

Santorum is a Catholic. While he has always acknowledged this, he has downplayed the specifics of his Catholic faith in order to curry favor with fundamentalist Protestants, many of whom regard Catholicism with roughly the same disdain they have for Mormonism.

For example, GodVoter.org, a self-appointed fundamentalist watchdog group, praises Santorum for his homophobia and his opposition to all forms of contraception, but then reminds fundamentalists that Catholicism is not true Christianity. Catholicism's "wayward historical fruits," according to the group, include "indulgences (allowing people to pay money to indulge in their sins), inquisition (torture and murder of non-Catholics), pedophilia, idolatry of Mary, dead 'saints' and Popes." These all "fundamentally contradict the Bible."

That kind of anti-Catholicism has been a staple of American fundamentalism and religious politics for a very long time, and represents the kind of bigotry American Catholics have tried to overcome. What may be less familiar is that Santorum's brand of Catholicism -- what we might call fundamentalist Catholicism, which insists on the "teaching authority" of bishops and popes -- has just as much contempt for Protestants.

Recently, Santorum accused President Obama of worshiping a "false theology." Some commentators read this comment as an appeal to the birther conspiracy crowd who insist that the president is secretly a Kenyan-born Muslim. Others saw this as a reference to the president's environmental policies

But while Santorum may have been speaking about the president's "world view," as he later put it, there is another context in which we might view that remark. The charge of "false theology" rings quite closely with the Papal Encyclical "Mortalium Animos" issued by Pius XI in 1928. Denouncing an ecumenical movement that tried to bring Protestants and Catholics together, Pius wrote "nor is it anyway lawful for Catholics either to support or to work for such enterprises; for if they do so they will be giving countenance to a false Christianity, quite alien to the one Church of Christ."

For the Vatican, in other words, the “false theology” is Protestantism.

Likewise, Santorum reports that he wanted to "throw up" over President Kennedy's 1960 speech in which he said "I believe in an America where the separation of church and state is absolute." That's an odd reaction from a Catholic, given that the separation of church and state in this largely Protestant nation has allowed Catholicism to flourish, and many chalked it up to overheated, hyper-ventilating campaign rhetoric.

But fundamentalist Catholics like Santorum have never accepted any separation of church and state and have always insisted on the primacy of their church in civil affairs. Pope Leo XIII, writing in 1890, declared, "No one can without risk to faith, foster any doubt as to the Church alone having been invested with such power of governing souls as to exclude altogether the civil authority."

That same pope, in 1885, also rejected the very foundation of American religious freedom: that we are each free to worship in our own way. In his encyclical "Immortale Dei" Leo XIII dismissed the idea "that no preference should be shown for any particular form of worship; that it is right for individuals to form their own personal judgments about religion; that each man's conscience is his sole and all-sufficing guide; and that it is lawful for every man to publish his own views, whatever they may be, and even to conspire against the State."

I don't know whether candidate Santorum subscribes to these pieces of fundamentalist Catholic doctrine as part of his unwavering Catholic faith. But that's just the point: While Santorum has denounced birth control and gay marriage as part of his religious crusade, he has been coy about whether his Catholicism extends to the rejection of Protestantism or the right to conscience.

In this sense, Santorum's crusade is not just against the 1960s and the Woodstock generation; it is against the 1560s and the Protestant Reformation generation. One wonders how his Protestant supporters will react once they figure this out.