The escalating nuclear debate in the United States has added a new dimension to ''church and state'' issues. Unlike other areas of controversy, it lacks clear-cut First Amendment implications. But the discussion surrounding churchmen's positions over nuclear armament is no less intense and emotional than that over school prayer, public financing of religious education, and the teaching of creationism in tax-supported classrooms.
The National Council of Churches (NCC) and, more recently, the National Conference of Catholic Bishops (NCCB) have taken the stand that nuclear proliferation is a moral issue - and therefore properly a religious one. They insist that churches have the responsibility to alert their parishioners to the potential devastation of nuclear war. On the other hand, President Reagan and many political conservatives see the communist menace as the real moral challenge. They say failure by the US to arm itself adequately (including development of nuclear weapons) would be a surrender to the forces of evil.
In May, in a setting where widespread news media publicity is being solicitated, the Roman Catholic bishops will review, and perhaps revise, a pastoral letter on nuclear warfare that has already sparked widespread criticism within and without the church community.
The NCCB fired its first antinuclear salvo late last year by condemning possible first use of nuclear weapons by the US and seriously questioning the morality of building a defense system that, if used, would kill large numbers of civilians.
Reaction to the bishops' statement was immediate. They were accused of delving into political matters with which they had little or no background or experience. Syndicated columnists Evans and Novak said they were guilty of ''nuclear heresy.'' And Michael Novak, a scholar and a Catholic theologian, called their position ''soft and romantic.''
President Reagan, coincidently or not, decided to deliver what some saw as a nuclear sermon to the National Association of Evangelicals (NAE) - a group from conservative Christian churches and agencies.
With fervent words, including analogies distinguishing ''good'' and ''evil,'' he urged ministers to oppose those members of the clergy who ''would place the United States in a position of military and moral inferiority'' by freezing nuclear arms production.
''I urge you to beware of the temptation of pride; the temptation blithely to declare yourselves above it all and label both sides equally at fault, to ignore the facts of history and the aggressive impulses of an evil empire, to simply call the arms race a giant misunderstanding and thereby remove yourself from the struggle between right and wrong, good and evil,'' Mr. Reagan told a cheering NAE audience.
Accolades were not forthcoming from others in the religious community. Some accused the President of mounting a political pulpit for partisan purposes. Bishop David Preus of the American Lutheran Church took issue with the implication that churchmen who favor the freeze would knowingly imperil the nation. And Rabbi Walter S. Wurzburger, president of the Synagogue Council of America, a group of Orthodox rabbis, criticized Mr. Reagan for injecting a ''sectarian note into a political issue.''
The nuclear controversy is virtually certain to get an airing in an international church forum this summer when religious leaders from across the globe gather in Vancouver, B.C., for a two-week conclave of the World Council of Churches.
Meanwhile, some political leaders - including those who might make a run for the White House in 1984 - are using religious settings to voice nuclear and antinuclear points of view. For example, Sen. Dale Bumpers (D) of Arkansas told a gathering from IMPACT, a religious action network supported by several dozen Protestant, Roman Catholic, and Jewish groups, that a national energy policy that relies heavily on nuclear power is ''wrong-headed.''
Some church leaders say that recent charges made on the CBS program ''60 Minutes'' and in a Reader's Digest article, ''The KGB's Magical War for Peace,'' are aimed, at least in part, at religious liberalism, including the antinuclear stance. The TV and magazine stories alleged that parishioners' donations are being siphoned off to subversive governments and revolutionary causes