THE EXTRADORDINARY irony facing Poland after this month's historic Communist Party congress is that the risk of Soviet military intervention may increase in direct ratio to the Poles' success in rebuilding their shattered economy.

For the time being, the Kremlin has chosen to tolerate a democratized, maverick Communist Party along with Solidarity, the powerful union. This continued tolerance was expressed by Soviet party chief Leonid Brezhnev in a message last Tuesday to Warsaw. He said he believed the Polish party is "undoubtedly capable of rallying all working people and mobilizing them for a resolute rebuff to anarchy and counterrevolution."

Brezhnev's telegram was no more than a recognition of present-day political reality. It represented, in the opinion of the best Washington analysts, a tactical move mbased on the theory that Poland will be unable to make its, economy work, and that, in time, the Polish pllitical experiment will collapse for economic reasons.

If this calculation is correct, moscow will have no need to intervene, it gamble having succeeded with the return of acceptable communist status quo in Poland. And thus far the Russians have bent over backward to avoid an invasion which would cause inclaculable world repercussion.

But what the Soviets can never permit is a viable Polish economy functioning in the context of growing political liberalization. That would pose dangers of contagion that might spread to the Soviet Union as well.

Ever since the Polish political upheaval began a year ago, internal progaganda in the Soviet Union, East Germany, Czechoslovakia and other communist countries has played up the dire conditions of the Polish economy, blaming Solidarity's strikes and the thoughtless permissiveness of the Warsaw leadership. The Poles were not working hard enough and had to be supported by "fraternal socialist countries," it was asserted again and again. Poland's failure to deliver raw materials, such as coal, to industries throughout Eastern Europe under Comecon common market arrangements imperiled jobs in East Germany and elsewhere, the argument concluded.

Such a propaganda line may have been responsible for the absense of any detectable support for Solidarity in other Eastern European countries.

Soviet strategy is finely tuned. The Russians are betting on Poland's inability to repair its conomy, in the hope that eventually Poland will have to turn back to them ideologically and, as a Soviet official remarked recently, to give up all that foolishness." But total economic catastrophe in Poland is not in the Kremlin's interest because the result would be anarchy and a breakdown of the regime. Such conditions would require Soviet military intervention, which Brezhnev and his associates do not desire.

Consequently, all along the Soviets have been aiding Poland economically -- just enough to prevent an overall collapse, but not enough to strengthen the reformist leadership. Without hard-currency reserves to buy crude oil on the world market -- as Poland has done in past years to meet roughly onehalf of its consumption requiremens -- Poland depends fully on Soviet petroleum which it buys on credit.

Poland is also receiving natural gas, iron ore and wool from the Soviet Union, and meat from East Germany. In the absence of such aid, the Polish economy would have come to a standstill months ago.

This is a point that the Soviets have been stressing publicly. They remind the unruly Poles where their "real security" lies. It is an argument pro-Soviet communists have been tirelessly proclaiming during the Polish party's power struggles, hoping to create a sense of dependency and even gratitude as Poland's economy keeps moving toward disaster.

For all these reasons, no serious analyst expects a sudden cutoff in Soviet aid. Clearly Moscow wants to remain in the Polish ballgame, and it believes that time is on its side.

The West wishes to play a part in the Polish crisis. At last week's economic summit conference in Ottawa, the seven leaders of the industrialized countries agreed privately that the West has a stake in Poland's continuing political liberlization, and there fore economic and financial aid must be provided. Although no "summit package" for Poland is envisioned, individual countries plan assistance measures.

Western governments and private banks have already extended until next Jan. 1 the due dates on principal and interest on Warsaw's staggering $27 billion debt. New rollover formulas over the next seven years are under consideration.

In response to an emergency request from Warsaw, the dnited States has agreed to supply 400,000 metric tons of corn for feeding poultry. There are also regular credit sales already in the works.

In the end, however, the Poles themselves must shoulder the burden of economic stabilization and reconstruction. Last week Prime Minister Wojciech Jaruzelski warned that "superhuman force" would be needed to overcome Poland's economic problems and that it may take five yars for the economy to return even to the weak performance of 1980.

Jaruzelski insisted the prices o food, natural gas, coal and housing must be raised immediately by 110 percent to do away with the government subsidies that for decades have kept living costs relatively low. He said wage increases -- 23 percent in the last year -- must be halted to avoid runaway inflation.

Previous attempts to increase food prices resulted in strikes and riots. Such an effort a year ago led to the great industrial strikes which spawned Solidarity and resulted in the ouster of Communist Party First Secretary Edward Gierek.

The question then is whether Poles are prepared for more sacrifices. And will Solidarity support the government in imposing price increases and wage freezes, and placing a moratorium on strikes?

As the recent Communist Party's special congress ended, after an unprecedented secret-ballot election of its Central Committee and Politburo, the leadership appealed for unity to save the nation. Two days, later, Solidarity responded by canceling planned strikes in Baltic seaports and by the employes of LOT, the national airline. The port workers said they had reached an agreement with the government "because of deep concern about the fate of the country and awareness of the difficult economic situation in Poland."

These responses suggest that common sense prevails among the Poles. But it is too early to reach conclusions. Like the Communist Party, Solidarity suffers from internal strife. There are moderates who believe in the need for compromise in the fnational interest, as well as radicals who advocate permanent confrontation to erode communist rule even further.

Solidarity's 10 million-member organization will not define its politics until it holds its congress, probably in September. Solidarity has not had time to elect a national leadership, and its democratic legitimacy must await the elections.

Soviet policies are based on the expectations that the anew communist regime and Solidarity will not cooperate sufficiently to bring about immediate economic stabilization followed by long-range reforms -- such as the decentralization of the national economy, and a self-management system in industrial and farm enterprises.

The Kremlin hopes that the Polish party's hardline wing, no longer dominant in the new Central Committee, will benefit from economic troubles and in time reassert itself.

The Communist Party's congress marked the end of the first phase in this astounding Polish revolution. The country now faces one even more complex. The new parliament, no longer a rubber stamp, must be elected -- most likely next year -- to reflect the liberal sentiment and the changes in the communist leadership. New laws must be approved to take into account the changed national situation. And Pole must learn how to function politically with the new realities.

However, Poland's future hinges on its economy. If the Poles make a go ot it, the future will be brighter in terms of creating a politically and economically rational society. Yet success may well unleash a brutal Soviet reaction.

Poland is placing before the Russians an awesome dilemma. Can they invade a nation to punish it for managing its affairs well? On the other hand, can they afford not to invade if Poland proves that a measure of political freedom is compatible with economic success outside the Marxist-Leninist mold?