If . . . If . . .

Whether in business or foreign policy, there are offers at each end of the spectrum--those you can’t refuse and those you wouldn’t touch with a 10-foot pole. The rest arrange themselves between the extremes, a necessary condition for bargaining or haggling over details.

The first good thing about General Secretary Mikhail S. Gorbachev’s latest arms-control offer is that it falls on that middle ground; it gives Soviet and American negotiators at Geneva something to haggle over. The second good thing is that Washington understands that. The fact that it is also good propaganda for the Soviets in their relations with Europe is too bad, but Washington can do nothing about that.

The offer is useful also because it will force President Reagan and his advisers to face up to the question about whether they really want arms control or whether the nation’s best interests lie in being free to explore avenues to nuclear superiority. For us and for most Americans, arms control is the clear choice. It remains an open question among some of the President’s advisers.

Washington will properly look for traps. For example, would dismantling all nuclear weapons, as Gorbachev proposes, make the world safe for conventional wars, a condition that history teaches is perhaps less brutal than a nuclear war would be, but brutal nonetheless.

Nor is it clear that Gorbachev intended to allow research on the “Star Wars” defense system to continue just because he mentioned testing and deployment but did not use the word research.

Those are serious questions that will keep a lot of Pentagon analysts late at the office in the months ahead. But they are questions to be answered in Washington and then negotiated at Geneva.

With the new proposal, the question becomes, to paraphrase the President’s paraphrase of Rabbi Hillel: If not this, what? If not now, when?