The zero option

And now something called ''zero option.'' That is what President Reagan has proposed to Leonid Brezhnev in advance of talks on theater nuclear weapons in Geneva starting this month. The idea is that NATO would cancel deploying 572 nuclear missiles in Europe beginning in 1983 if the Soviet Union eliminated all the intermediate-range missiles it now has targeted on Europe.

Let it be said first that the President is to be applauded for publicly putting a proposal on the table. He clearly hopes to quiet West European public opposition to his policies, dispel a bellicose image, and seize the diplomatic initiative from the Soviet Union. It definitely was time to make a move of this kind.

The question is what ''zero option'' is. Is this an opening negotiation position on which the United States and its allies are prepared to be flexible and reasonable? Or is it primarily a propaganda gambit aimed at blunting growing neutralism on the continent? Most negotiations, of course, begin with each side offering an extreme formulation. No experienced negotiator offers the bottom line first. It can therefore be reasonably expected that the Reagan administration is prepared to bargain for an agreement.

Few think the proposal, as outlined publicly, will be acceptable to Moscow. The Russians are asked to remove missiles already in place (and more than 1,000 warheads) while NATO would simply scrap a future program. No doubt the Russians will point out that the NATO position does not take account, for instance, of the existing British and French intermediate-range nuclear forces that have a capability of hitting the USSR. It is also doubtful the Russians would accept on-site inspection if the US presses on this issue.

But it was encouraging to hear the President, in his speech to the National Press Club, say that the US goes to Geneva ''willing to listen to and consider the proposals of our Soviet counterparts.'' The Russians, after all, should understand the very real concerns aroused by the stationing of powerful mobile SS-20s aimed at Western Europe. NATO has no comparable land-based missiles that can reach the Soviet Union (although it was assumed even before positioning of the SS-20s that NATO submarine warheads provided a deterrent and, unlike land-based weapons, were invulnerable). The major worry seems to be the heightened accuracy of the Soviet missiles and the danger this poses to NATO's land-based nuclear stockpiles.

Many complex questions will need to be gone into.Some analysts, for instance, question whether the Pershing II and cruise missiles which NATO plans to install are the best way to resolve the present imbalance. The Russians, the argument goes, perceive such missiles as a significant threat to their command and control system and even military forces and therefore might simply be spurred to build up even more. Perhaps there are other options to explore.

In any event, nothing will be lost and possibly much gained by Mr. Reagan's stress on deep cuts in arsenals - including intercontinental strategic weapons. We welcome the new attention to preventing nuclear war rather than musing on how it might be fought. The ''zero option'' for theater arms in Europe may not be realistic as presently defined. But it is a starting point. The task now is to prepare well for Geneva and, in the President's words, ''see how far we can go.''