THE CZECH author Milan Kundera once wrote that the struggle of man against power is the struggle of memory against forgetting. He was remembering how the angry Western reaction to the 1968 Soviet invasion of his country had quickly cooled. Today, the struggle against forgetting has lost more ground--this time in a neighboring country, Poland.

Last week President Reagan sent Deputy Secretary of State John C. Whitehead to Warsaw. He started negotiating with General Jaruzelski to lift the economic sanctions levied in 1981. The aim was to end Poland's nearly six years of political isolation.

Poland's political reconciliation with the West had picked up speed a week before, when Poland's General Jaruzelski visited Italy and was received with full diplomatic honors. Italian industrialists pledged to invest several billion dollars during the next several years.

IT WAS AS if everyone had forgotten about the coup d'etat Jaruzelski had engineered and about his violent crack-down against Solidarnosc. At the time, Western nations reacted to such outrageous act firmly, isolating Poland politically and levying economic sanctions.

The anger didn't last very long.

DURING THE month of Jaruzelski's mission to Italy and Whitehead's diplomatic initiative, Poland played host to Japanese prime minister Nakasone. The country will receive Britain's Margaret Thatcher and the French and German foreign ministers during the coming months.

The official visits that have taken place fully sanction Jaruzelski's new role as full head of state.

This new phase has taken place even though there has been no major political improvement in the conditions that caused the sanctions in 1981. Actually, since martial law was declared, life for the Poles has worsened. Nearly 25 percent of the population live below the nation's poverty line. In a single decade the quality of life decreased by 30 percent.

The government-sanctioned newspaper, Politika, denounced the lack of basic goods like soap and detergents. For the first time since World War II, the paper reported, the schools of Warsaw are infested by lice.

WHEN CARDINAL Karol Woytila was elected pope, Poles expected to have a strong champion beyond their government's reach. John Paul II did initially give strong support to the Solidarnosc movement and the Danzig agreements.

Now, even the Pope has decided to abandon his attitude of confrontation with the Polish regime in favor of compromise.

In the face of the Pope's bland opposition, Jaruzelski has restored the Church's old privileges and created new ones, giving the Church a large measure of freedom to educate the young and to assist the needy.

The great losers in all this are Lech Walesa and the other Solidarnosc leaders. They are out of jail, but--without strong support from the Church--they have fallen into oblivion. In 1983, Virginio Levi, Director of the Vatican daily, L'Osservatore Romano, was fired for writing an editorial saying what the Church would not admit: that Walesa and Solidarnosc had been sacrificed.

In the end, Western financial support will allow Jaruzelski to end the Polish recession--and quell the frustration of the people. The regime of Jaruzelski is on its way to a definitive stabilization and the West is strongly contributing to its success. Just like Brezhnev had foreseen.