A summit primer

LET us clear away some of the haze that surrounds the Reagan-Gorbachev meeting in Washington. None of the demonstrators who traveled to Washington to air their pro or anti sentiments about dealing with Russia are going to have the slightest effect on the pending arms control treaty.

The treaty is finished. It was stitched together over seven long years of negotiating and maneuvering. It will remove all middle-range Soviet SS-20 weapons from Europe and the Far East, and withdraw all US middle-range Pershing 2 and ground-launched cruise missiles from Europe. The final details were completed last week in Geneva.

All Ronald Reagan and Mikhail Gorbachev can do in Washington today and tomorrow to the middle-range weapons treaty is to sign it. They can sign or not sign. It is too late for changes.

The demonstrators might conceivably influence the course of talks about other matters. Once the middle-range treaty is signed, Mr. Reagan and Mr. Gorbachev will talk about a next step in arms control. The logical next step would be a first-stage rundown in the number of the huge long-range nuclear weapons with which each superpower threatens the other.

That subject automatically raises the related subject of conventional weapons. The United States will not give up its long-range nuclear deterrent against the Soviets unless the Soviets will give up some portion of their ability to launch a land war attack on Western Europe in a denuclearized situation.

Also, there will be talk about the possibilities of ending US aid to the rebels in Afghanistan if the Soviets will cut back on their aid to the rebels (contras) in Nicaragua.

Is the treaty to scrap the middle-range weapons fair, and safe?

Yes. It will restore the situation that existed before the Soviets deployed 270 SS-20 medium-range ballistic missiles in Europe.

The United States responded by deploying 108 Pershing 2 missiles and 256 ground-launched cruise missiles into the European theater.

The European allies and the US were deeply troubled by the Soviet deployment of the SS-20s in Europe. They could reach every capital and all the major military targets of the allies in Western Europe.

The pending treaty would restore the situation that seemed satisfactory to the United States and to its allies before the Soviets changed it by deploying the SS-20s, with an improvement: There will be mutual verification on site.

Elimination of the middle-range weapons does not leave NATO open to a Soviet conventional offensive. The NATO allies will still possess thousands of short-range weapons, plus the nuclear forces of Britain and France, plus nuclear weapons aboard allied naval vessels offshore.

Why then is there so much opposition to the middle-range treaty?

Primarily because it is a first step that could lead the way to further steps.

Many Americans for various reasons do not want the United States to be doing any business at all with the Soviets. The Reagan administration took office with a yearning to overthrow the present Soviet regime. Caspar Weinberger, then secretary of defense, pushed hard for a policy of economic boycott, on the theory that a tight enough boycott by all the Western countries could actually bring down the communist regime.

The failure of the Reagan administration to organize and carry out a massive boycott of the Soviet Union has been a source of deepest disappointment to many of the original supporters of the Reagan cause.

When Mr. Reagan signs the middle-range treaty, he will be abandoning the idea of trying to unseat the Soviet regime. The act of signing will confer legitimacy on the Gorbachev regime, it will recognize its continuing existence, it will mean that the US, even under a right-wing Republican President, is willing to coexist with it and do continuing business with it. It amounts to abandoning the cause of ``roll back.''

The Joseph C. Harsch column of Dec. 8 referred to Soviet support for the Nicaraguan contras. In fact, of course, the Soviets support the Sandinistas.