Score one for Jerry Falwell. Yes, indeed, the pastor of the Divine Church of the Direct Mail, scourge of homosexuals, pro-choicers, civil libertarians and nuclear freezeniks, has landed one right on the button. He criticized Walter Mondale for using his religious background to criticize President Reagan's use of religion. Falwell ought to become a shoe salesman. The one he has put on Mondale fits.

Appearing on "Face the Nation," Falwell took Mondale to task for mentioning that both his father and his father-in-law were ministers before engaging Reagan on the religious issue. Mondale has done this repeatedly, most recently in his speeches before Jewish and Baptist groups. In both, he criticized Reagan for politicizing religion.

Both speeches were good -- and gutsy to boot. In both, Mondale cited the phrase coined by former Rep. John Buchanan (D-Ala.) -- "moral McCarthyism." It's a telling phrase because it suggests what moral McCarthyism and political McCarthyism have in common -- intolerance.

Political McCarthyism was marked by an intolerance of political dissent; moral McCarthyism is marked by an intolerance of religious dissent. The outcome is the same in both cases: the debate gets limited to only those who can first prove that they mostly agree.

One hallmark of the McCarthy era was the exclusion of some people from the debate altogether. Hysterical anti-communism became the prerequisite of loyalty to the country. Even before Sen. Joseph McCarthy himself made his now famous speech in Wheeling, W. Va., the political atmosphere was such that the Democrats, including President Harry Truman, felt obliged to proclaim incessantly their anti-communism before they could even suggest that crazed anti-communists were trashing the Bill of Rights. The Truman loyalty review boards, for instance, were created not only because there was a handful of so-called subversives in the government but to show that Democrats, too, were anti-communists. The boards proved that all right; but they also proved Truman bought the premise.

The same thing has happened with moral McCarthyism. Ministers such as Falwell and politicians such as Reagan have so escalated the debate over the proper place of religion in American politics that it has become incumbent on Mondale to first trot out his religious credentials before taking them on. Thus Mondale, citing his pedigree, told the Baptists that he was a "PK" -- a preacher's kid.

It hurts to concede anything to Falwell, whose mailings are a lot less charming than he is ("Militant homosexuals are plotting a dangerously different future for America"), but he has a point -- maybe one he doesn't get. The so-called religious debate has been limited to those who can prove that they are rligious. There are, though, countless millions of Americans whose parents were not ministers, who do not go to church, whose morality and Americanism are nonetheless unimpeachable -- and who have a real stake in the outcome of this debate.

And there are even millions of Americans -- brace yourself -- who are either atheists or agnostics but who remain both citizens and people whose rights ought to be inviolate.

When Mondale proclaims his own religiousness in order to battle the president, he accepts both Reagan's and Falwell's premise. That's not dissent; that's conformity -- the essence of any kind of McCarthyism, moral or political. But if the religious debate is about anything, it's the right to be a nonconformist and still be heard -- to be judged on your argument, not your proclaimed piety, and to have your politics considered separate from your religious beliefs.