A FEDERAL DISTRICT court in Idaho ruled last week on some important legal questions concerning the process of amending the Constitution. Because the case at hand specifically concerned the Equal Rights Amendment, much attention was focused on the impact of the decision on the drive for ERA ratification. A closer look, however, suggests that the heavier impact may fall elsewhere.

Support is growing in the country for a series of constitutional amendments to ban abortion, to require a balanced budget and to authorize school prayer. These are measures on which the Idaho decision impinges. In the years ahead, some of the very people who decried that decision last week may be citing it gratefully to slow the ratification process of these other amendments and to make the procedure as difficult as possible. Some of those who hailed the decision may bite their tongues.

The case, Idaho v. Freeman, concerned two questions: does Congress have the right to extend the time period for ratification of a constitutional amendment by the states and do individual states have the right to reverse themselves after having agreed to an amendment? Judge Marion Callister decided against Congress on the first question and for the states on the second. This may be bad news for supporters of the ERA, who haven't had much good news of late, but it could be a useful precedent for opponents of New Right amendments now being seriously considered in Congress and in state legislatures. They will be able to use the words of a conservative judge to argue against extending the time for ratification of a prayer amendment. They will have available the Idaho precedent to lobby for rescission of a state's hasty ratification of, say, a balanced budget amendment.

The Idaho decision may yet be reversed on appeal. More likely, time will run out on the ERA-- three more states must ratify it by June 30--before the Supreme Court can complete action on an appeal. But until it is reversed, the Idaho opinion is good law and valuable precedent. As the Justice Department advised the court, the lawsuit raised "issues of historical and national significance whose resolution affects not only the proposed ERA, but all constitutional amendments, the role of Congress in proposing them and the role of the states in ratifying them." If Judge Callister's decision makes the process of amending the Constitution more difficult, so be it. It was never intended to be easy.