During the Republican National Convention in New York City this past August, a closed, invitation-only campaign rally, consisting mostly of evangelical Protestants, was held in a packed ballroom at the Waldorf-Astoria hotel.

One of the principal speakers, Senator Sam Brownback of Kansas, urged the audience to "win this culture war" which is being waged on several fronts, including the fights against legalized abortion, same-sex marriages and judicial rulings that uphold the separation of church and state.

Regarding the last point, the senator claimed that the courts have conducted "a 40-year assault on the Constitution" to the point where it "is no longer separation of church and state. It is removal of church from state."

There were several ironic aspects to this scene. The socially conservative, evangelical Protestant crowd enthusiastically applauded the words of a religious turncoat. Although born and raised a Methodist, of an evangelical type, Senator Brownback later converted to Roman Catholicism, of an Opus Dei type.

For many conservative Protestants, Catholicism is not an authentically Christian denomination. It is a cult. When such Protestants use the word "Christian," they do not have Catholics in mind.

Nevertheless, conservative evangelical Protestants welcome the active support of new and life-long Catholics like Senator Brownback and Senator Rick Santorum of Pennsylvania, who was Brownback's sponsor when he was received into the Catholic Church. They agree not only on abortion and same-sex marriages, but also on national defense, the war in Iraq (irony #2: Pope John Paul II, idolized by the right, condemned this war as immoral), tax cuts, assault weapons and the environment.

For purposes of political convenience, however, a don't-ask-don't-tell approach to Catholicism currently prevails. And it also seems to work in the opposite direction.

Conservative Catholics whose 20th-century precursors held the view, "Outside the (Catholic) Church, no salvation," keep their theological estimation of Protestant "heretics" in check. The re-election of President Bush is deemed too important to allow a fracturing of this right-of-center religious coalition.

Irony #3, therefore, is how readily both sides --- a certain type of conservative Catholic, on the one hand, and many conservative evangelical Protestants, on the other --- subordinate their faith-convictions to their political interests. One would ordinarily expect them to allow nothing to stand in the way of, much less trump, their deeply-held religious beliefs.

The truth is that the kind of pre-Vatican II Catholicism that new converts like Senator Brownback and born Catholics like Senator Santorum wish to restore or believe has never ceased to exist included the clear teaching that "error has no rights," that Protestants are not members of the church, that Protestant spouses in a mixed marriage cannot be buried in the same consecrated ground as their Catholic husbands or wives, and that every non-Catholic denomination is a false religion, without valid ministry, valid sacraments or the spiritual wherewithal to guide its members to heaven.

Conservative Protestants in this same pre-Vatican II period regarded the Catholic Church, in its turn, as a false religion permeated with superstition, idol-worship and priestcraft. When such Protestants referred proudly to the United States of America as a "Christian" nation, they really meant "Protestant." Many were, after all, descendants of those who had hung out the "No Catholics Need Apply" signs in the windows of their business establishments.

Perhaps numerically the conservative evangelical Protestant congregations that Karl Rove is counting on to help insure the re-election of the President are more representative of American Protestantism than are the mainstream Protestant and Episcopal churches. That is a matter for sociologists and historians to determine.

But from the Roman Catholic side, one can say with some confidence that the kind of Catholicism represented by Senators Brownback and Santorum does not typify American Catholicism generally, nor is it entirely congruent with the full range of Catholic teachings on a wide variety of doctrinal and moral issues.

To be sure, official Catholic teaching strongly condemns abortion and homosexual behavior, but it also condemns unjust wars (as Pope John Paul II condemned the war in Iraq), capital punishment, laying unfair tax burdens on the poor, damaging the environment, closing the doors of one's country to immigrants, and denying workers the right to unionize.

Moreover, the Catholic Church no longer teaches that "error has no rights" or that Protestants and other Christians are beyond the pale of salvation. Indeed, even non-Christian religions, beginning with Judaism but also including Islam and other world religions, are beloved by God and, in their own way, instruments of salvation for their own adherents.

Some day conservative evangelicals and pre-Vatican II Catholics may see each other once again through theological rather than political lenses. If so, stand back.

Father Richard P. McBrien is the Crowley-O'Brien Professor of Theology at the University of Notre Dame.