We recently celebrated the seventh anniversary of Solidarity. Who is ''we''? Well, that's the rub. ''We'' is a diminishing number of people, including Poles. And one asks oneself the question: How long has Ronald Reagan been in office? Because what some people are saying is that there is a causal relation between the two events. This is a serious charge. And a charge weighted with paradox, given that President Reagan is the most energetically anticommunist president we have ever had.

Last week, speaking in California, he proposed no less than that Mikhail Gorbachev lead his country into a civilized relationship with the world, that the Soviet Union become a good neighbor. ''In April of 1987,'' the president said, ''we asked that a date be set this year for rapid and complete withdrawal from Afghanistan; in June, that the Soviets join us in alleviating the divisions of Berlin and begin with the dismantling of the Berlin Wall; that the Soviets move toward self-determination in East Europe and rescind the Brezhnev Doctrine.''

But the speech in which these liberating words occur coincided with two developments on the international front. The first was the announcement by West German Chancellor Helmut Kohl that in deference to U.S. leadership he would abandon his insistence on retaining control over the 72 Pershing 1-A missiles. The second was the announcement that the United States would be prepared to retreat from the rigorous standards of verification on which we had originally insisted, standards that were no longer realistic given blah, blah and blah. William Safire closed his commentary on these events with some withering words: ''That's why a solid speech vanished into California's evanescent mists.''

Now we hear from Eugene Rostow. Prof. Rostow was our principal disarmament adviser in the early days of the Reagan administration, and he flat out warns us that the intermediate-range nuclear forces (INF) treaty by no means guarantees a safer world. ''The Soviet Union is counting on the West to relax in the glow of an INF agreement. It expects the West to cut military budgets, abandon the Strategic Defense Initiative and forget the Reagan Doctrine. Five or 10 years hence, the Soviet Union thinks, it would have consolidated an untouchable lead in space and other high-technology weapons.''

What does the eminent Prof. Rostow recommend? Begin with the easy ones. He believes that testimony before the Senate will persuade objective observers that we are better off with reduced intermediate missiles than with no intermediate missiles. It is easier to verify missiles in place than missiles underground, which is where the Soviet Union could keep them in the event glasnost does not mean an end to Soviet cheating.

But then he makes the kind of proposal one associates with Ronald Reagan. In fact, it is the kind of thing Reagan has been saying to the Soviet leader for years, and most recently in California: live up to the Yalta agreement, giving Eastern Europe the right to determine its own political future. ''Stalin's breach of that promise was the key turning point in the Cold War. A commitment by Mr. Gorbachev to carry out Stalin's promise could be the key turning point in a retreat from what Mr. Reagan called the lid on top of the nuclear volcano.''

People used to laugh at the whole idea of a rollback -- one needs to reach back to John Foster Dulles in 1952 to remember the words.

But we keep hearing that we face a new situation. The president keeps imploring Mr. Gorbachev to prove that this is so. We revive the relevant rhetoric even as the one postwar movement with true promise -- more convincing than the Prague Spring of 1968, less volatile than the Hungarian student fighting of 1956 -- gets weaker and weaker, the fate of Solidarity on its seventh birthday. And we accept, in lieu of genuine progress, merely a shift in nuclear strategy by the Soviet Union. No second lieutenant would tell us that any inhabitant of the West will be safer the day after INF is consummated than he is today.

So why not the same kind of chorus that energized the United States 15 years ago behind other causes? Remember ''Stop the Bombing''? Why not: ''Bring Down the Berlin Wall,'' ''Russians out of Afghanistan,'' ''Free Elections in Eastern Europe''? A mobilization of that kind of pressure, responding to the high idealism of Reagan's speeches, which gets lost in the workaday world of conferences, negotiations, treaties and summiteering.