It sounds paradoxical when R. T. Davies claims that "credit to Poland makes no sense" (op-ed, April 9) while the Polish pope, the Polish Episcopate and Lech Walesa have called for the lifting of remaining economic sanctions, particularly those on access to still available sources of credit. Is the leader of Solidarity "defying logic," as Davies suggests, or is Walesa trying to help his cause?

Poland is not an independent state. The legal structure of Solidarity was smashed under the direct threat of a Soviet invasion. The chance of a compromise that could have restored a dialogue with Solidarity was lost when the West European nations refused to join the United States in any meaningful economic pressure on the Soviet Union. Even symbolic sanctions against Moscow, inroduced after the invasion of Afghanistan and the crackdown on Solidarity, were quietly lifted.

This year, four leading American banks lent the Soviet Union $400 million at unusually low interest rates to buy American and Canadian grain. In 1984 alone, East Germany received $2.5 billion in Western credits. Last year, even Bulgaria received $125 million from Western banks. Rumania, which has the most repressive regime in Eastern Europe, was admitted to membership of the IMF and enjoys most-favored-nation status in its trade with the United States.

Economic restrictions against Poland alone can be effective only within the narrow margin of freedom that Gen. Wojciech Jaruzelski is either willing or compelled to exploit. President Reagan made sanctions reversible and offered aid if the Polish government would reach a modicum of reconciliation with its people. This policy of carrot and stick has not been totally unsuccessful.

In an effort to lift the economic blockade and regain espectability, Jaruzelski allowed the pope to visit Poland in 1983. Soon after, 2,000 political prisoners were released and martial law was lifted, at least on paper. Because other repressive meassame time and top leaders of Solidarity remained in jail, the response of the Reagan administration was limited to concessions of marginal impact. One year later, all 600 political prisoners -- including 11 leaders -- were released. (One of them, Jacek Kuron, went directly to the U.S. Embassy in Warsaw to express his appreciation. He and his colleagues recognized that they owed their freedom to American policy.) Washington responded by withdrawing its veto against Polish membership in the IMF.

Those who follow Polish affairs had little doubt that the Polish regime might rearrest all or some of the Solidarity activists. This did happen in the case of Michnik, Lis, Frasyniuk, Moczulski and several others. With these few exceptions, however, most of the released prisoners remain free. Like Walesa, they daily walk a tight rope by engaging in above-ground activities in a twilight zone between a legal and illegal life. They are subject to considerable harassment, but the constant reminders of their presence in public life are met with a kind of angry tolerance by the regime. This means that open opposition -- without, of course, any legal sanction -- does exist in today's Poland.

Lech Walesa faces a difficult dilemma. He is opposing the totalitarian government, but he wants to avoid anything that could hurt the Polish people more than it hurts their rulers. A continued freeze on Western credits (with the exception of loans granted to help repayment of old debts) will make Poland the pariah of Eastern Europe. The progressive impoverishment of its people is not conducive either to stronger resistance or to greater independence from the Soviet Union. According to Walesa, the Polish regime should not be provided with an exuse for blaming its approaching economic disaster on sanctions and U.S. policy.

America has its own strategic stake in Poland. Developments there have largely destroyed the internation precipitous decline to the suppression of Solidarity. The northern flank of the Warsaw Pact has been weakened. Popular resistance has continued to frustrate the Jaruzelski government's efforts to "bring Poland back to socialism," as demanded by Mikhail Gorbachev. The church remains strong and independent. Mosjoy greater freedom of expression than in any other communist country. Last year, between 5 million and 7 million Poles boycotted the Soviet- style general election.

Solidarity has survived as the only massive underground organization in the Soviet orbit. It refrains from violence, but furthr deterioration of living conditions could lead to an uncontrolled popular explosion, which Jaruzelski might not be able to suppress without Soviet help. The political repercussions of a blood bath in the heart of Europe would not be confined to Polish borders.

Nobody, including Walesa, recommends a repetition of the errors committed in the '70s when R. T. Davies was our ambassador in Warsaw and Western credits were pumped into an inefficient and overcentralized communist economy with no strings attached.

Jaruzelski cannot expect the lifting of remaining sanctions unless he can improve the political climate in the U.S. Congress, the Western media and public opinion by releasing the prisoners of conscience still kept in his jails under inhuman conditions. Nor can he ask for aid unless he takes advantage of the help already being offered through the Church Fund. He cannot hope to get credits from the IMF or the World Bank unless economic reforms make the system less wasteful.

Jaruzelski should not, however, be put in a position in which he has noth gain in his dealings with the West. Solidarity and the Polish people will be better served by a dialogue rather than by the present deadlock.