Of all the words spoken by politicians and statesmen since martial law was declared in Poland, one rings special historical bells: Yalta. It is the name of a city on the Black Sea in the Soviet Crimea, but also a symbol for much that has happened in Europe since World War II.

In February, 1945, Franklin D. Roosevelt, Winston Churchill and Joseph Stalin met for seven days at Yalta to try to decide how to organize postwar Europe. They settled some issues, but postponed most of the hardest ones. Poland's future was a major point of discussion, but no decisions on Poland were made.

Years later Yalta became a code word in American politics. According to the anti-Roosevelt view, Yalta symbolized Roosevelt's sell-out to Stalin near the end of the European war. FDR's critics said he gave Eastern Europe to the Soviets at Yalta.

Historians have generally rejected that apocalyptic vision of what happened. Scholars have concluded that the Yalta meeting was essentially a means of ratifying the most obvious outcome of World War II and deferring most of the trickiest questions the war had raised.

In terms of today's Polish crisis, recalling Yalta raises the issue of "realism," a quality that Roosevelt hoped desperately would distinguish his efforts at European peacemaking in 1945 from those of Woodrow Wilson 27 years before. According to one interpretation of Yalta, it is only realistic to accept the existence of Soviet-style dictatorships as permanent fixtures of East European life. But it is also arguable that those inherently unstable dictatorships insure that the present arrangements in Eastern Europe cannot be permanent.

In a recent interview with The New York Times, West German Chancellor Helmut Schmidt said that the West "decided in a meeting in Yalta to practically divide Europe into spheres of influence," and the West has accepted ever since that "the countries east of the River Elbe . . . are not under the West's rule."

Those nations east of the Elbe, Schmidt indicated (though he avoided spelling it out specifically) are under Moscow's rule instead, and although "the West has tried to influence developments" in Eastern Europe, "never did anybody try to intervene by force. And I hope nobody will, because that would mean war."

Schmidt's formulation is an interesting revelation of German attitudes, but it does not speak to the deeper issue of how best to maintain European stability.

The goal at Yalta and in subsequent meetings of the wartime allies was to establish stable European arrangements, so that World War III would not follow the second war as inexorably as World War II followed the first.

To that end, Roosevelt and Churchill accepted the idea that the Soviet Union would have legitimate long-term security interests in Eastern Europe. That was the point of the deal Churchill offered to Stalin in Moscow in October, 1944. On a slip of paper that he passed across the table to the Soviet leader, Churchill suggested mathematical formulas for postwar "predominance" in Eastern Europe. He suggested that the Soviets enjoy 90 percent predominance in Romania, 75 percent in Bulgaria, 50 percent in Hungary and Yugoslavia, and 10 percent in Greece. In each of these countries, according to Churchill's proposal, Britain and its friends would enjoy the influence that was left, from 10 percent in Romania to 90 percent in Greece. Stalin accepted the deal on the spot.

But there were grave flaws in this proposition, as there were in the Yalta agreements later. For one, Churchill never spelled out what 25 or 50 percent influence in one of these countries might mean in practice. For another, Churchill skipped over Poland. In October, 1944, Poland wasn't on the list he passed to Stalin. And at Yalta, though Poland took up the most time of any subject on the agenda, it was left unresolved.

Prof. Adam Ulam of Harvard, a prolific scholar who has written extensively on these matters, noted last week in an interview that even Stalin wasn't sure he could get away with the imposition of Soviet-style communist dictatorships in Eastern Europe until 1947-48. What Stalin discovered was that no piece of paper could alter the influence that came to the party that had the dominant military position in East Europe.

So in the end the West had to accept the proposition that these communist dictatorships were in fact one of the consequences of World War II. They happened. Exploiting first of all the Red Army's military position and secondarily the western powers' acceptance of legitimate Soviet security interests in Eastern Europe, Stalin built a sphere of influence and cordoned it off with an "iron curtain."

That was the reality that East German workers tried to challenge in 1953, that Hungarians rose up against in 1956, and that Czechoslovakian intellectuals tried to subvert in 1968. In each episode the West stood aside. As Schmidt put it, "never did anybody try to intervene by force." Stalin's sphere of influence survived and survives still.

But that does not mean that nothing has changed. The East German uprising was squelched in a few days in 1953; the Hungarian Revolution was snuffed out in weeks. But the Czechoslovakian flirtation with "socialism with a human face" lasted for more than six months, and the Polish "renewal" sparked by the formation of Solidarity in August, 1980, lasted for 16 months.

The Soviet sphere of influence was established in an era when the iron curtain was more than a phrase and interaction between East and West was nearly nonexistent. In 1956 Budapest was an outpost cut off from the western world; today Hungary owes $6 billion to western banks and the Levi Strauss Co. is manufacturing blue jeans there. The iron curtain has been shredded by trade, travel, radio broadcasts and money-lenders.

Now there is a different kind of Europe. Eastern European prosperity depends largely on the capitalist world, both for markets and for credit. Today's Soviet political objectives--keeping American intermediate-range missiles out of Western Europe, for instance--can only be attained with West European cooperation. At the same time, the Soviet Union has established an unassailable military predominance on the European continent, so no other continental power can seriously threaten it. Only America has that ability.

The peoples of Eastern Europe were brutalized by World War II, and it took them a long time to recover. But now they have recovered, and they share the rising material aspirations that long ago inspired the West. Judging by events in Czechslovakia a dozen years ago and Poland recently, East Europeans also have spiritual aspirations that cannot be contained so easily. Younger generations don't accept the realities their parents perceived, as the young firebrands of Solidarity demonstrated.

The initial West German reaction to martial law in Poland seemed to reflect a belief that the West would have to accept this turn of events in Warsaw just as it accepted the crackdowns of '53, '56 and '68. This was Schmidt's message in his interview. Stability in Europe, he seemed to be arguing, depends on adherence to the Yalta division between East and West.

But do the present arrangements really offer stability? On neat, dozen-year cycles, there have been major upheavals in Eastern Europe. If one of these were to get out of control--one in East Germany, say, which has always been by far the most sensitive of the satellites for Moscow--the world could suddenly face the most dangerous moment of the nuclear era.

Yet the record suggests that the Soviets cannot prevent these upheavals. After 1968 they bought off Czechoslovakia with a flood of consumer goods, but they did not transform Czechoslovakia into a viable socialist society.

It is once again in desperate economic straits, and now the Soviets have many fewer resources to apply to the problem. Poland is obviously in disarray, and martial law will not substitute for an effective social compact that might unite the country so it could work to revive the devastated Polish economy. Only the Hungarians have found what appears to be a genuinely stable national path, but this was the fortuitous product of luck and Hungarian cleverness, and it too would be vulnerable if, for example, western credit dried up.

Hungary has defied the Soviet model, but done so quietly. Censorship is relatively light in Hungary. Travel restrictions are not severe. Central economic control has been largely abandoned. But on foreign policy matters the Hungarians remain slavishly loyal to Moscow, and there is no open challenge to the "leading role" of the communist party.

Prof. Seweryn Bialer of Columbia, one of the country's leading Kremlinologists, proposed last week that the United States use the Polish events to make a new approach to the Soviet Union. Bialer suggested that the United States send this message to Moscow:

"Look, we recognize the strategic interests you have in Eastern Europe. We have great sympathy for these interests--we recognize you need a cordon sanitaire. But what do strategic interests have to do with social and political change? You've failed to make these societies work. So let's try to divorce these two questions--within limit, of course. Let these countries be at least the most liberal in the communist world. You can't afford this kind of trouble every five or 10 years . . . ."

Was Yalta a permanent arrangement? How could it be? Yalta and the other postwar arrangements were no more permanent than the underlying conditions that bred them. All of those conditions have changed, with one crucial exception. The Soviets still believe that in return for the 20 million people they lost in World War II, they deserve neighbors who won't threaten their security. And they have the military power on the ground to enforce that view.

But this is not the same as enforcing stability, and as Prof. Bialer observed, the Soviets have failed on this count. Their failure suggests that both Moscow and the West should both want to change the status quo now to achieve stability, even if it is just Hungarian-style stability. But neither side may be able to perceive this common interest, let alone act on it.