SO THE EAST-WEST strategic dialogue, a painful decades-long effort to find increments of security in restraint, is inching forward again after the halt brought about by the Soviet invasion of Afghanistan. The new impetus is the product of the reconnaissance that West German Chancellor Helmut Schmidt conducted for the Alliance in Moscow. The Carter administration, enfeebled as it is by its assorted wounds and by the election ahead, has not been able to pick up any pieces of negotiation since Afghanistan. Mr. Schmidt is in better political shape, and in a different political condition, and he could make a try.

What has actually happened? SALT II is on the shelf, if not in the deep freeze, and this promises an uncontrolled strategic buildup that it remains in the American interest to address. Meanwhile, there is the special problem created by Soviet deployment -- unprovoked and so far uncountered -- of new, accurate and powerful SS20 missiles trained on Europe. The expectation has been that these Euromissiles, and other missile systems based in and around Europe, would be taken up in a SALT III. Even before Afghanistan, however, a question mark hung over SALT II. Watching Moscow deploy SS20s at a better than one-a-week clip, the Europeans decided last December that spring in 1983 they would deploy matching new American missiles on their soil and that, meanwhile, they would try to negotiate both clusters of new missiles away.

First the Kremlin tried bluster, saying it would not consider negotiating unless NATO rescinded its decision to deploy. American anxieties focused specifically on Mr. Schmidt, who had proposed a three-year missle freeze. It was feared that if Moscow accepted a freeze, the Europeans might halt preparations for the deployment required to match what Moscow has already done, and that if Moscow rejected a freeze, the Europeans might simply be intimidated and forgo any preparation or deployment at all. On his Moscow trip, however,, Chancellor Schmidt apparently held firm enough so that Soviet leader Leonid Brezhnev dropped the demand that NATO rescind its deployment decision before a negotiation can begin. But Soviet SS20 deployment will continue.

In these matters, there is never a point where it is prudent to say that the deal is made. Moscow will keep working on the Europeans to put off their deployment preparations. If new Soviet-American negotiations begin, they will surely go slowly, and the Kremlim will try to convince the Europeans that the United States alone is at fault. Whether the Soviets have decided to give Jimmy Carter the boost of starting talks this year, or to defer to Ronald Reagan and wait, is uncertain. One thing, however, is clear. Nothing will bolster the prospects of negotiation more than for Europe to stick to the preparation schedule needed to deploy the new NATO missiles in 1983. Without that, any negotiation will be a charade and Europe will be neutralizing itself.