When the people set limits on nuclear arms

The Easter weekend peace demonstrations in various countries were but one example of a public yearning to set limits on nuclear arms. President Reagan's evolving support of arms control has reflected the impact of public opinion. So has Congress's consideration of a nuclear freeze proposal that struggled upward from the grass roots.

Regard for public opinion also impelled the Reagan administration's full-scale publicized reply to the second draft of a pastoral letter on nuclear arms prepared for the US National Conference of Catholic Bishops.

The recently announced third draft is in some respects closer to administration positions - it calls for a curb rather than what had amounted to a freeze on nuclear weapons, for example. But, according to spokesmen, the letter has not lost its moral thrust.

A key intention remains unchanged. It is to keep public policy responsive to public opinion. Specifically: ''to encourage a public attitude which sets stringent limits on the kinds of actions our own government and other governments will take on nuclear policy.''

Indeed, as suggested above, the formation of a public determination to influence nuclear policy was well under way both in the United States and abroad before the US bishops seized what they call the ''new moment'' in public debate. Bishops in other countries also have been hammering out pastoral letters on the nuclear issue. Conservative Catholic critics - such as Michael Novak in an article occupying almost a full issue of the National Review - have welcomed the bishops' effort even while disagreeing with some of their antinuclear positions.

Mr. Novak uses the same phrase as the US bishops' letter: ''To say 'no' to nuclear war is both a necessary and a complex task.'' Only Mr. Novak continues, ''. . .especially since saying no doesn't make it so.''

Here is the challenge once again to an aroused public to maintain the democratic pressures on their leaders to act in accord with reducing the arms race and preserving peace. This is not to ignore the Soviet threat or the necessity for Moscow to join in the process. It is to test each policy and action of one's own government in relation to the goal of preventing nuclear outbreak.

The American bishops are reported to have been spurred toward their enhanced public concern for preserving human life from nuclear war by way of being consistent with their great public concern for preserving life in the womb from abortion. They will debate and vote on the third and presumably final draft of their pastoral letter next month. Once approved by a two-thirds vote, it will be widely disseminated and made part of the educational program in Catholic schools and institutions.

The debate among Catholics already suggests that this will not be the end of the matter. Individuals may continue to arrive at different practical positions on the basis of similar moral motives.

But the point will not be lost on Catholics or anyone else that it is important for all to consult such motives in performing their duties as citizens. At the moment this means letting government know how far it can go on nuclear policy in the name of the people.