WHEN THE United States first contemplated sending the new medium-range nuclear missiles to Europe, a great frightened cry went up in protest. Many European voices asserted that the Americans were recklessly increasing the risk of incinerating their countries. They did not even pause to acknowledge that the first request for such missiles had in fact come from Europeans, starting with Helmut Schmidt, who were then complaining of American lack of care for the allies' security.

Now -- two turns later -- the United States is talking about the possibility of negotiating the withdrawal of those same missiles. The European reaction is hardly one of relief. On the contrary, it's reported to be yet another rumble of anxiety that the Americans are once again failing to take adequate account of Europe's basic defense requirements.

Each turn in American nuclear policy seems to be greeted with an equal and opposite reaction in Europe. An amusing folk custom? Well, in some respects, yes. But it's something deeper as well: a reflection of the central political tension in the Atlantic alliance. One of the partners in that alliance is very much more powerful than any of the others, and the second most powerful, West Germany, has undertaken a firm commitment not to possess nuclear weapons. This disparity in control over the weapons leads to deep ambivalence toward the plans for managing them and a certain perennial discontent.

One reaction is the militant pacifism that has now been widely embraced among the churches of Germany and northern Europe generally. It was particularly audible in the demonstrations against the new missiles. The other side of the European debate is rooted among the defense experts who, regardless of party and nationality, acknowledge that the conventional military forces in eastern Europe greatly outweigh those in western Europe. Withdrawing the nuclear weapons on the western side, they warn, would only increase the danger to the West. These are the people you are mainly hearing now, although accuracy requires that some account be taken of the permanent floating critics, who express despair over American policy whatever it is.

All sides share the concern that too much of their security depends on decisions by another country several thousand miles away which, unlike themselves, has the good fortune to be separated from the Soviets by two oceans. The strategic arms control negotiations between the United States and the Soviets always heighten those concerns. Nearly all Europeans welcome the negotiations. But the sight of the negotiators working on subjects that sharply affect fundamental European interests, with no Europeans at the table, troubles them -- no matter that the Europeans (Britain and France) whom Moscow has now invited to a separate nuclear table are not at all eager to get there.

The remarkable thing about the Atlantic alliance is that, after 37 years, it is still in good working order. There's nothing quite like it in the history of modern diplomacy. But it will remain in that condition only so long as people who make nuclear policy in Washington pay close attention to the signals of doubt and dissent that come from western Europe.