This week's news has recorded the political decline of two of the most prominent revolutionary leaders of the decade - Lech Walesa of Poland and Yasser Arafat of the Palestine Liberation Organization (PLO).
Both have fallen on hard times for the same reason - inability to curb the more radical elements in their organizations. Both may enjoy a twilight chapter of some residual importance. But, for both, the days of rising and important influence are over. Both are likely to play declining and minor roles, if any, on the world stage from this week on.
In both cases, the climactic moment in their careers occurred well before the setbacks which events of the past week have recorded.
In the case of Yasser Arafat the crucial moment came after President Reagan launched his Middle East peace proposals on Sept. 1, 1982. The general situation at that time was particularly favorable to the Arabs and quickly became more so.
The Israelis already had shocked President Reagan by the fierceness and extent of their invasion of Lebanon, the bombing of Beirut, and the entry of Israeli troops into Beirut itself. They turned down his peace plan on the day after it was launched, hard. Three days later, on Sept. 5, they announced that they would proceed at once with an expanded plan for building settlements for Israeli Jews in occupied West Bank and Gaza lands, in defiance of the President's proposal for a freeze on all such construction.
On Sept. 16 news began to leak out of the massacre of Palestinians in Sabra and Shatila refugee camps, which were within the Israeli area of occupation, by Lebanese rightists.
On Sept. 18 the President declared that ''all persons of decency must share our outrage and revulsion over the murders.'' In the same statement the President said: ''We have today summoned the Israeli ambassador to demand that the Israeli government immediately withdraw its armed forces from west Beirut.''
Never before had there been such general sympathy for the Arabs, and disapproval of Israeli behavior. Not before or since has Mr. Reagan been so disapproving of Israel and so ready to be helpful to the Palestinians.
That was the moment for Mr. Arafat to come forward, embrace the President's peace plan, declare his readiness to make peace with Israel, and agree to go to a conference table prepared to accept the existence of Israel.
The opportunity for seizing the peace issue existed right down through the negotiations between Israel and Lebanon. With Mr. Arafat's support, King Hussein of Jordan could have joined those talks. For a brief few hours it seemed that this would happen. But inside Mr. Arafat's organization the radicals took over. He was unable to deliver the PLO to the peace table when his case was at its strongest.
The story of Lech Walesa is identical in essentials. He built the Solidarity movement in Poland. He led it through its early days. It was fabulously successful so long as he was leading and the rank and file listened to his words of caution.
His peak period was from 1980 through the first six months of 1981. During those times he won the right of Solidarity to exist, legally. He brought down the inefficient and corrupt Polish regime headed by Edward Gierek. Pressure from him and Solidarity led to a reform inside the Communist Party itself. Control went over from the Stalinist wing to a reform wing. Reform in the party went so far as to permit secret balloting for leadership of the party.
Such things had never happened before in any East European member of the Warsaw Pact. Such things did not happen again. By spring of 1981 Lech Walesa was a true national hero who had achieved wonders in modernizing and liberalizing the government and the Communist Party of Poland.
His time of crisis came in June. Many of his followers, elated by their success, wanted to go faster and further - much further. Walesa cautioned them. He declared that Solidarity was not a political party. He warned against challenging the state and party further. He called for an end to demonstrations. He called for everyone to get back to work.
The young radicals in the movement did not listen. They dreamed of liberating Poland from the Soviet yoke and taking over control of the government from the Communist Party. Lech Walesa became a figurehead. The end came in December with martial law and the arrest of Walesa himself.
This week Yasser Arafat was a wanderer through the Arab world. He had been expelled from Syria, where most of his armed forces are deployed and are now under Syrian orders. Rebels in his movement, aided by Syria, were attacking and defeating units loyal to him in Lebanon's Bekaa Valley. Arafat is a figure with a past. Arab governments other than the Syrian receive him and listen to him. But he no longer can deliver the PLO movement in international affairs. He no longer commands an army.
This week the news has been filled with reports about Mr. Walesa's status. He says he will keep on with his work in Poland. The Vatican denies that the Pope has ordered him to cease and desist.
But the larger fact is that the serious negotiations about the future of Poland are going on between the Polish state and the Polish Roman Catholic Church.
Pope John Paul II met twice with the Polish head of government, Gen. Wojciech Jaruzelski, during his Polish visit. They obviously discussed a broad plan for cooperation between state and church in the economic rebuilding of Poland. The church proposes bringing Western investment funds into Poland and obtaining a relaxation of Western sanctions against Poland.
The Polish government is willing to deal with the church because, unlike Solidarity, it is willing to observe the biblical injunction ''render to Caesar the things that are Caesar's.'' In Poland the Communist Party is Caesar.
Lech Walesa tried to keep to that same road, but failed. Since June 1981 he has been a figurehead, a symbol, a slogan. This week it was clear that real power in Poland today lies with the state and the church and that the two are in a stage of being willing to cooperate with each other.
The radicals in both the PLO and Solidarity have converted powerful revolutionary leaders more into romantic memories than men of the future.