When the so-called ''religious'' factor surfaced in the 1960 presidential race with the nomination of John F. Kennedy for the presidency, John Coleman Bennett attacked it head on. The Presbyterian minister (at that time one of the nation's leading liberal Protestant spokesmen) - together with his illustrious theological colleague Reinhold Niebuhr - soundly scolded fellow churchmen for suggesting that a Roman Catholic president would not be able to resist pressures from the Vatican.
The Rev. Dr. Bennett says he believes that such admonitions are no longer necessary today. ''Religious prejudices are breaking down, particularly between Roman Catholics and Protestants,'' this theologian says. He notes that in the last two decades, the ''Catholicism'' of presidential aspirants, such as Edmund Muskie and Edward (Ted) Kennedy, has attracted little notice. Now, in fact, Democratic vice-presidential nominee Geraldine A. Ferraro openly speaks of her Roman Catholic faith.
The Rev. Dr. Bennett attributes what he considers significant progress today toward religious tolerance by the major faiths to broader dialogue among Catholics, Protestants, and Jews; diminished fear of so-called ''Catholic power'' by the US public at large; and the decline of bigotry in the mainstream churches.
''Racist doctrines are no longer commonly accepted - as they were as late as the 1950s'' Dr. Bennett says. ''[Then] many liberal white churches didn't accept blacks as members.''
However, He does not, deny that religion still plays a key role in national and international controversy. He cites, the official anti-abortion stand of Catholics as a source of consternation to ''pro choice'' forces. Also the differences of opinion on the question of Israel's relations with the United States and with its neighbors. ''But this has nothing to be with anti-Semitism, '' he insists.
Dr. Bennett has preached religious tolerance and cooperation, together with racial understanding, for over half a century. And he is still doing it today through his lectures and writings. His hallmark has been a relevant and active religious faith, compassion and care for all mankind, and a global view of government.
In the 1950s and '60s he was imbued with the spirit of the civil rights movement. And as longtime professor and later president of the prestigious Union Theological Seminary - and a leading liberal spokesman in New York - he denounced racial and religious bigotry. He also used the platform of the intellectual Protestant publication Christianity and Crisis - whose editorial board he chaired for many years - to preach this social doctrine.
Today - from a more pastoral setting at Pilgrim Place, a community for senior but active theologians and former missionaries - Dr. Bennett focuses on the nuclear issue.
He says the central conflicts between church and state in the near future in the US will likely pertain to foreign policy, especially in relation to the use of nuclear weapons.
The theologian points to two factors he says will increase the resistance to particular wars: (1) statements from US Roman Catholic authorities supporting the the principle of conscientious objection to military service; (2) the prospect that nuclear wars would produce large number of Christian nuclear pacifists, among both Protestants and Catholics.
Dr. Bennett's theological philosophy is intertwined with a global view of society. He plays down the Soviet military threat (''The Russians no longer believe they can win a nuclear war'' and ''They are as much afraid of us as we are of them'') in much the same way he dismisses what some still see as the dangers of Catholic power.
''The struggle for mutual security must include cooperative efforts [by the US and Soviet Union] to deliver the world from nuclear [destruction],'' Dr. Bennett says.
John Bennett's views of church and state seem to cut across ideological lines. Many liberals - whose views he generally embraces - might criticize him for seemingly assaulting the wall of separation by advocating public aid to parochial schools. Conservatives reject his stand that nuclear proliferation and political repression in Central America are properly ''religious'' concerns.
The theologian insists, however, that he supports the basic concept of ''separation.'' He says religious institutions need to be free from control by the state. At the same time, the state must be protected from ecclesiastical control that would tend to abridge individual religious freedom. At the same time, Dr. Bennett avers that separation of church and state ''is favorable to the health and vitality of churches.''
On the other hand, the Protestant churchman stresses that religious freedom is not primarily freedom from religion. In his chapter on church and state in a recent book (''Reformed Faith and Politics,'' University Press of America, 1983) , Dr. Bennett advocates the expression of ''civil religion'' in the context of government. He writes:
''There should not be an artificial inhibition of all religious expression by the president and others who represent the state. The provision of chaplains of Congress and many other legislative bodies shows how deeply rooted a recognition of civil religion is in our institutions.
''Lincoln's Second Inaugural was one of the greatest American religious utterances, and our tradition would be much poorer without it.''
The theologian does caution, however, that such public expression of religion should be ''under the criticism of churches and synagogues to keep it from becoming a form of national idolatry.''
In line with this, Dr. Bennett staunchly defends the right - even the responsibility - of Christians, including clergy, to speak out on political and social issues affecting society's well-being.
''The church by its very nature is a universal community,'' the theologian holds in his book. ''Its faith is in God who has no favorites among the nations. This means that the Church begins with a concern for the people of all nations. Yet its members are citizens of one nation and have special responsibilities for its well-being and for the well-being of their nearer neighbors.... When members of the Church become aware of the claims both of their loyalty as citizens and their loyalty as members of the universal community they know that they face problems, even conflicts, within themselves.''
''This is as it should be,'' Dr. Bennett insists.