Being Mikhail Gorbachev -- or any Soviet leader, for that matter -- means never having to say you're sorry.

That's the astonishing aspect of Gorbachev's fabulously profitable Easter surprise: that the Soviet Union will "freeze" European deployments of SS20 missiles and await developments. If the United States also freezes its deployment of equivalent intermediate-range missiles (Pershing 2s and cruise), Gorbachev intimates, the Soviet freeze would be indefinite.

We have said no to the proposition, which is probably the right answer. But we have said it so artlessly as to guarantee Gorbachev a cheap propaganda triumph.

In a warier world, where free peoples read their newspapers carefully, Gorbachev's proposal would be identified (if welcomed) as the long overdue reform of the bully who's been terrorizing the otherwise weaponless main streets of Europe for 10 years.

The Soviet SS20 deployments, commencing in the mid-1970s, are almost exclusively responsible for the so-called "Euromissile" problem. Before those deployments, there was no significant nuclear missile threat in Europe. The NATO inventory included some aging short- range missiles, incapable of reaching the Soviet heartland and many nuclear warheads, mostly for artillery use, of "battlefield" range. Britain and France independently maintained (as had both for many years) small nuclear deterrents, by comparison with the Soviet nuclear arsenal numerically insignificant. Neither deterrent affected a supposed European "nuclear balance." There was no such thing.

Then, for reasons not fully understood but certainly including the perennial hope of bullying Western Europe into quasi-neutrality, the Russians created the Euromissile problem. Week by week, year after year, they relentlessly deployed the SS20, a triple-warhead mobile missile of 1,500-mile range, targeted on Western European aim points.

This was a new, gratuitous and menacing twist in the nuclear game. It was as if the United States and NATO had commenced targeting a new generation of modern nuclear missiles on Warsaw, Budapest, Prague and hundreds of other "threats" in East and Central Europe.

The Europeans grew duly concerned, and in 1977 Chancellor Helmut Schmidt of West Germany said, in effect: If the United States makes no response, default may indeed serve the longstanding Soviet purpose of splintering NATO.

U.S. strategists were cool to Schmidt's argument. They saw no military reason to ape the Russian move. But they knew that deep at heart the Europeans had never quite believed in the U.S. pledge to use strategic nuclear weapons in defense of Europe.

So we said: If NATO wishes, the United States will deploy 572 updated "intermediate-range" missiles in specific response to the SS-20, a political response to a political worry. But of course any balance of power, nuclear or not, is at heart political.

This, then, is a capsule history of the problem in connection with which Gorbachev has made his first grandstand play.

Our response, a fair one, is that we shall not join in a freeze that would leave a huge imbalance in warheads, perhaps 10 to 1. In turn the Soviets, as they always do, played their phony Anglo-French card. What about their deterrent? they ask.

Easy. The British and French deterrents are national, not NATO; mostly sea-based; small; dwarfed by Soviet strategic arsenals; and in any case unrelated to any "European" balance of nuclear missile power.

Notwithstanding the record, which is easily understood, there again prevails -- by our default -- the fantastic misimpression that the Soviet Union is eager to relieve nuclear anxieties in Europe, while the United States is stubbornly augmenting them. In propaganda contests, the edge is usually to the bigger hypocrite, and the Russians know few rivals at the tribute vice pays to virtue.

But really. The Reagan administration has been monumentally blockheaded -- there is no kindlier way to say it -- about all this. In kissing off Gorbachev's offer with the usual gesture of offended rectitude, the Reagan White House assumes that self-righteousness (our Cold War forte, as hypocrisy is the Russians') tells its own story. It is also assumed that free peoples are well enough briefed to see through Gorbachev.

Neither is the case. The "arms race," as the Soviets call it, looks to most people, most of the time, like a frightful muddle. Here and in Europe, millions find it too scary to think about -- literally. And they may be beyond help.

But millions of others, honestly confused or uninformed, might be reached with patient and artful explanation. We owe them at least that. These days, sanctimony is not enough.