After more than two years of interagency study and debate, President Carter has finally announced a comprehensive plan for storing and then permanently disposing of the nation's military and commercial nuclear waste. Make that after 20 years, for it has been that long that the nuclear industry -- and, for a while, the government -- has insisted that nuclear waste disposal would be easy, if only a few anti-nuclear critics would get out of the way.

To his credit, the president recognized not only that nuclear waste disposal is a real and tough problem, but that the social and political barriers to its solution, are at least as great -- if not greater than -- the technical ones. Therefore, the president concluded, the only way to arrive at a generally acceptable program is to make haste slowly. That conclusion underlies the two main features of his plan; a conservative, step-by-step approach to the resolution of the many technical uncertainties and an aggressive effort -- despite the certain delays -- to involve state governments and public opinion in federal decision-making all along the way.

The president's cautious approach to the technical issues means that several different sites for a permanent waste repository -- as well as sites in different geologic environments such as salt, grantie, clay and others -- must be tested and thoroughly evaluated before a final selection is made. This in turn means that the actual deposal site, which will take a decade to build, cannot be chosen until at least 1985. This has angered some members of Congress who believe construction should begin immediately.

Predictably, the proposal has also been attacked by those who think it moves too fast. One of the most difficult nuclear waste issues is whether states should have the right to veto the construction of a waste facility within their borders. The president announced that "the basis of our relationship with the states" will be, in the jargon of this business, "the principle of consultation and concurrence." Concurrence, of course, implies the right not to concur, but the president wisely left the job of deciding whether it amounts to a veto, and how a veto right might be exercised, to a newly created State Planning Council made up of governors, elected state officials and heads of various federal agencies.

He merely pointed out -- and it badly needs saying -- that, to make "concurrence" work, states would have to "participate as partners . . . not as adversaries" and that nuclear waste disposal is "a national, not just a federal, responsibility." Sen. Edward Kennedy immediately criticized the president's decision for not explicity recognizing what Mr. Kennedy called "the right of states to reject the construction of waste facilities within their borders."

The president's proposal includes many other decisions -- and for each of them Congress boasts at least one critic. The Senate Energy Committee has already reported out a bill that bears no resemblance to the president's proposal. Many other committees are acting on other bits and pieces of the nuclear waste issue -- each going in different directions and acting with conflicting assumptions and biases. Resolving the differences could take years. Congress would do well to take the president's proposal -- which strikes a sensible balance between rushing ahead and striving to win an unattainable universal consensus -- as a new starting point. The country has failed to reach agreement on nuclear era. It can surely afford to wait the few extra years it will take to develop a technically sound and politically workable probram -- so long as it is understood that it cannot afford to wait forever.