It is the religious groups of the left that have been most in evidence on the American foreign policy scene in recent years, but now religious groups on the right are gearing up to get into the act in a major way.

Not for them the pro-"peace," pro-dente, pro-development, pro-Third World policies of the National Council of Churches, the U.S. Catholic Conference, the Friends and their liberal activist like. The religious fundamentalists or evangelicals are on the other side of the fence and opposition to communism anywhere it raises its head.

Its advance on the home front, evident especially in respect to social issues, is what has led the Protestant religious right to seek to expand its interests and ambitions into the national security field. It is also inclining secular conservatives to look fundamentalists as an additional constituency available to support conservative security goals.

At the Republican convention, fundamentalist gave a crucial boost to the anti-abortion, stop-ERA planks in the GOP platform. Riding the tide, Howard Phillips, the ideologue who runs the Conservative Caucus, soon called a press conference to denounce the prospect of any convention or party role for Henry Kissinger, the fundamentalists' pet foreign-policy hate. Phillips announced that a new majority coalition was awaiting only Ronald Reagan's summons to be born. It would group "pro-family" and anti-government-interference elements on the domestic side and musclee-flexing nationalists on the foreign side.

On issues, the religious right, having paid little organized attention to national security in the past, tends to look outside its own ranks for leaderships -- to politicians such as Sen. Jesse Helms (R-N.C.) and, of course, Ronald Reagan, and to public policy groups such as the Heritage Foundation and the American Security Council. As one of the movement's own experts, Phillips cites retired Army Brig. Gen. Albion Knight, the Conservative Caucus' anti-SALT circuit rider. Television evangelist Jerry Falwell is getting into foreign policy, too.

On principles, the religious right speaks for itself. It sees foreign policy as an instrument to ensure that the nation has the freedom and power internationally to nourish the values of freedom internally an intent to proselytize is denied. Foreign policy is regarded not as a means to serve familiar interests like security or prosperity or to achieve a certain balance in the world but as the medium of the nation's unavoidable engagement in a continuing conflict of good and evil.

To "people who get into foreign policy through moral considerations," as Phillips puts it, the main enemy is not poverty, racism and conventional social justice, as it is to Jimmy Carter, but communism, which would enslave the individual to the state and which denies God to boot.

The liberals -- and the secular conservatives sharing their premises -- who have long run American foreign policy are put in the category of benighted souls who do not understand that the United States has a special placer and a special mission in God's eyes.

The religious right teethed on the Panama Canal, the issue whose chance discovery by Reagan in 1976 did as much as anything to make him and the right what they are today. Issues now engaging its attention include: the defense budget SALT, communism in Central American and the Caribbean region, and Israel, which fundamentalists support on the basis of biblical teachings.

The Catholic right was a strong influence on American policy after World War II while the Catholic societies of Eastern Europe were falling under communist domination. In the last 15 years or so, the religious left in the United States -- Catholic, Protestant and Jewish -- has had little competition to speak of from the religious right on security issues. But Protestant fundamentalists, though coming from a less international-minded segment of American society, were bound to catch on to the opportunity to test their influence in the broader arena. The currents that have been drawing fundamentalist religious movements even deeper into politics around the world were sure to make their mark here.

I am not sympathetic to the foreign policy ideas of the religious right and I am not cheerful about its claim to a larger role. It threatens to add a gross weight and a shrillness at the end of the spectrum that needs more a measure of civility and finesse. But watch out.