We are approaching the days (weeks? months?) when the Senate Foreign Relations Committee will hear the arguments for confirming the treaty arranged by Reagan-Shultz to remove intermediate nuclear weapons from Europe. The Panama Canal Treaty of 1979 kept the Senate committee listening to testimony for 16 weeks. Proponents of the treaty insisted that vital interests of the United States would not be jeopardized; rather, they would be enhanced by the proposed treaty. Ten years having gone by without a crisis in which the new arrangements in Panama proved damaging, it is fair to say that at least in the short term the treaty was sound. It is by no means confidently said that 10 years from now the vital interests of the United States will not have been affected by the INF Treaty being proposed.

The main trouble is that the damage is really done, and it makes little difference how the Senate acts. Henry Kissinger, for example, plans to testify. And he will give his reasons (as he has done eloquently in a recent issue of Newsweek) why he thinks the treaty is not merely bad but profoundly bad. But we cannot talk in the subjunctive mood about the damage the treaty would do if ratified. Kissinger's point is well taken, that the damage has already been done.

The years 1981-1983 will probably be viewed by historians as the watershed. During those years, Ronald Reagan flatly insisted on proceeding to deploy the intermediate-range nuclear missiles first demanded by Helmut Schmidt in 1977 when the intimidating shadow of the Soviet SS-20s reached the Bundestag. The reasoning then was that nuclear equality between the forces of the Soviet Union and those of the United States worked to the disadvantage of the West in that the superpowers having neutralized each other's ultimate forces, their penultimate forces emerged as of dominant military relevance. And these are, of course, the conventional forces. The Soviet Union, with its deployment of the SS-20s, was really engaged in adding nuclear strength to its preponderant tactical advantage. The benefit that lay waiting for the allies was that by deploying counternuclear weapons, they neutralized at one and the same time not only the Soviets' SS-20s but also the massive Soviet tactical arsenal.

The European left, plus European ambiguists, fought as hard as the American isolationists in 1940 and 1941 to prevent deployment, but Reagan said: That is the way it is going to be. And Americans abroad, joining with realistic Europeans, ardently detailed the advantages to be got from the countervailing nuclear weapons. The deployment of these weapons was the most significant achievement of the foreign policy of Ronald Reagan.

And then, suddenly, we were hoist by our own petard. The Soviet Union recognizes that a) it probably doesn't need SS-20s to intimidate Europe; b) if it did, it could cook them up without any real problem -- the United States is accustomed to Soviet violation of treaty terms as witness our continuing toleration of the radar station at Krasnoyarsk; c) if it didn't suit the Soviets to reassemble their SS-20s, they could with absolute impunity put their mobile SS-24s just where they wanted to -- yes, right up to the Brandenburg Gate. And if they did so, what would they face?

Omaha, Neb., when you come down to it. The nuclear forces of France and Great Britain are hardly enough to sustain a challenge by the Soviet Union. And our nuclear artillery, carried by bombers and launched from submarines, is unlikely to be used in a situation in which the Soviet Union declares that any such weapons, American weapons whose use is directed by Americans, will be interpreted as a nuclear provocation that would invite retaliation in the heartland of America.

The United States won the battle in deploying our cruise missiles and our Pershings. It has now lost the war. Lost it because political landslides of geological dimension have taken place in Europe. Ask yourself one question alone: If the Senate were to reject the INF Treaty, could we then proceed with the full deployment of the scheduled intermediate-range missiles?

Preposterous. The question would then be not should the United States continue with deployment, but should the United States remove those weapons it has already deployed?

The diplomatic game, played by the State Department since Reykjavik, has changed drastically the politics of West Germany, which sees itself now as, for all intents and purposes, disarmed. Great Britain's opposition party wants unilateral nuclear disarmament, which is not very far from what they are getting under the INF Treaty. The Low Countries and Scandinavia are formalizing the neutrality they have always inclined to.

Some treaty. Where do we go now?