THE POLISH government wants everyone to know it has the money in hand to pay the current installments on its enormous foreign debt. The checks, it says, are in the mail. The money presumably comes from the Soviets--just in time to avert a massive Polish default this month. But the same crisis is likely to recur repeatedly throughout the year.

Poland's debt is the result of the deeply flawed economic strategy that it pursued in the last decade. The central idea was to borrow heavily abroad to build factories producing consumer goods for export. The exports were then to pay off the foreign loans and, in addition, buy the imports to raise the Polish standard of living. Unfortunately, the Polish government insisted on maintaining the same rigid centralization of control that had contributed heavily to all the previous Polish economic failures. The goods shipped into world markets generally failed to compete, either in quality or in price. Meanwhile the two oil crises of the 1970s held down consumer demand in the West.

But the Soviets have good reason to avoid, at least for the present, a Polish default. Western banks tend to regard the Soviet Union as the guarantor of all the loans to its Eastern European clients, and a Polish failure would threaten to cut off commercial credit to the whole Eastern bloc. That in turn would spread Poland's paralysis to its neighbors.

Perhaps the Soviets also wish to avoid, or at least postpone, a financial blow that would fall particularly severely on West Germany. The Germans-- both the government and the commercial banks-- hold by far the largest share of the Polish debts. It's partly because the German governments of the 1970s were enthusiastic supporters of d,etente and the trade relationships on which it was based. West Germany is leading the opposition within the Atlantic Alliance to sanctions against the Poles and the Soviets, and its chancellor, Helmut Schmidt, is now in Washington to argue the case with President Reagan. It's hardly an opportune moment for the Soviets to permit a failure that would be costly both to the chancellor and the German banks.

How long will the Russians keep paying the installments of the Polish debts? It's impossible to say. But if a default is to be prevented, it is they who will have to do it. The West, and particularly the United States, ought to be ready to make substantial concessions to assist economic and political reform in Poland. But it's up to the Russians to finance martial law.