THE SUMMIT-EVE American charge that the Soviets have been violating a previous agreement is in dispute. But whether the charge is valid or not it has a certain important illustrative value. It demonstrates the rubbery quality of compliance and verification and the importance of getting all the facts and following appropriate procedures. The administration alleges that the Soviets moved some radar equipment and components in violation of the Antiballistic Missile Treaty of 1972. Soviet spokesmen at once denied a violation and said they had invited American on-site inspection. We are not sure whether Soviet compliance has been any more painstaking here than American verification, which seems at the least incomplete. It does not build confidence in the merits of the allegation, moreover, to learn that the U.S. government was divided on whether to make it and that some high officials consider it ''technical.'' Arms control is too important to be clouded by casual or premature complaints of Soviet misconduct.

There's a better answer to the question of Soviet compliance with treaty obligations, and that is, as President Reagan asserted last night, the unprecedented range and penetration of the verification measures written into the missile treaty that is due to be signed next week. These measures, product of a new Soviet seriousness, include broad mutual opportunities to inspect production, deployment and destruction sites. Had this sort of inspection been permitted earlier, the Soviets would have had to make a very different set of calculations about whether to build, for instance, the infamous radar at Krasnoyarsk.

It is true, as used to be said at Rand (and perhaps still is), that we've never found anything the Soviets successfully hid. But they've never successfully hidden anything that we've found, and now we get a chance to find a lot more.