Few people may have noticed, but this summer a decade of political wisdom in Eastern Europe has been tested and found deficient.

Ever since the harsh repression of the Czechoslovak reform movement in 1968, the accepted belief among foreign diplomats and dissidents in Eastern Europe has been that the stability of the governments placed in power by the Kremlin rests on their ability to satisfy the rising material expectations of their peoples.

The theory was borne out in Poland in 1970 and 1976 when government announcements of massive price increases sparked widespread strikes and riots.The increases were rescinded and political calm was brought through an infusion of Western loans and Soviet subsidies.

Les dramatically, in Czechoslovakia most people showed that they could accept the purges and suppression of human rights that accompanied the "normalization" era that followed the 1968 ouster of reformist Communist Party leader Alexander Dubcek -- provided their living standards steadily increased.

The prevalent political mood quickly turned apathetic, as young Zechs who had demonstrated against the Soviet occupation of their country switched their energies to acquiring a car and a summer house.

This delicate equation between economic progress and political stability now has been upset.From the Baltic to the Adriatic, the summer of 1979 has witnessed growing economic strains in the form of rapidly rising prices, widespread failure to meet production norms, and the shadow of the worldwide energy crisis which has finally caught up with Eastern Europe. Yet so far, despite considerable grumbling, there is no sign of an imminent explosion.

This is perhaps surprising when one considers the scale of the economic problems confronting the Soviet bloc. Czechoslovakia and Hungry have announced their biggest price increases for a decade while Poland is relying on rationing by shortage. Virtually all bloc countries are chronically in debt to the West and most plan huge grain imports this year to offset poor harvests. The price of gasoline has been increased by between 40 and 100 percent throughout the region.

Put in human terms, as a Hungarian leader tried to do recently, this means that families about to buy a car or build their own home may have to revise their plans. Finance Minister Lajos Faluvegi called on every Hungarian consumer to live more modestly, even a little differently. In short, Eastern Euope seems to be entering the age of expensive energy and no, or at any rate slow, economic growth.

For the West, it is a familiar enough situation. What makes it particularly painful for East Europeans is that their living standards are already that much lower than in the West -- and their outlets for letting off frustrations correspondingly fewer.

This fall, when workers return to their factories from their summer vacation poorer in real terms than when they left, could be a worrying time for the region's Communist leaders. It was after all Karl Marx who taught that there is a strict correlation between a society's economic substructure and its political superstructure. The present evidence suggests that in Eastern Europe's case the correlation may not be as watertight as Marx predicted.

The history of the region since World War II, when the Soviet Union created a chain of satellites to guarantee its security, demonstrates the capacity of people to tolerate the intolerable. What seems like a crisis one day becomes the normal state of affairs the next. Both rulers and ruled have learned important lessons from the past that make future explosions on the Hungarian or Polish pattern less likely.

Perhaps the most important new skill acquired by Eastern Europe's political is that of flexibility. The politicians now in power have yet to succumb to the delusion of infallibility that sealed the fate of Czechoslovakia's Antonin Novotny in 1968 and Poland's Wladyslaw Gomulka in 1970. They have learned how to identify potential opposition and defuse it before it becomes too threatening.

This flexibility was reflected this summer in the unprecedented care that was taken to explain the mounting economic problems to the public. The effort went furthest in Hungary. It is hardly a coincidence that, despite its violent past, Hungary is also probably the most stable country in the Soviet bloc today.

But other politicians have also learned the Hungarian lesson. Czechoslovak leaders, for example, departed from traditional Community practice by admitting for the first time that the energy crisis is not just a capitalist phenomenon, but also vitally affects the socialist economies.The Polis, Czechoslovak, and Hungarian governments also reacted swiftly to gasoline restrictions imposed by Romania by allowing their citizens to travel to the Bulgarian Black Sea coast through Yugoslavia, although this appears to have resulted in a sizable increase in the number of defections to the West.

The flexibility of the rulers has been matched by a growing political realism among the ruled. This has been exemplified by Poland, ostensibly the most likely candidate for the next explosion, where both church and dissidents have concenjrated their efforts on securing piecemeal improvements rather than dreaming about a radical transformation of society. The reason is that they are aware that past upheavals have solved nothing and do not want to provoke a Soviet intervention.

Last year a team of dissidents who produced a sweeping critique of the Polish economy surprised everyone with their modest proposals for reform: they stuck to what they thought had a chance of being accepted.

A prominent Yugoslav sociologist commented: "I do not know whether this realism is a sign of political maturity or simply long-term hopelessness. If you define politics as the art of the possible, then I suppose it's maturity. As a result of the bitterness of past experience, the peoples of Eastern Europe now have a very good grasp of the possibilities and limitations of their geopolitical situation. They know that if they push too much, they might lose what they already have."

Finally, the Kremlin too has updated and refined its techniques for maintaining its hegemony over Eastern Europe. The Red Army is still stationed in all Soviet bloc countries except Bulgaria and Romania, but it is kept largely out of sight and day-to-day control is exercised in more subtle ways. Oil and natural gas pieplines criscross the region -- and the taps are controlled by Moscow. The Soviet Union is also Eastern Europe's largest trading partner.

The rapid pace of economic integration has meant that few bloc states could break away from their dependence on the Kremlin, even if they wanted to.

However stultifying it may have been, Soviet control over Eastern Europe has also given this notoriously unstable region its longest period of political stability for centuries. Thus the very longevity of the governments created by the Kremlin in its own image has endowed them with a legitimacy of sorts.