CAMBRIDGE, MASS. -- Forty years after George C. Marshall came to Harvard to announce what came to be called the Marshall Plan, Sen. Joseph Biden (D-Del.) tried stepping into the great man's shoes. With a nod to Marshall, Biden outlined the foreign policy of the generation he claims to lead. He delivered a puffy speech, citing people whose names he could not pronounce, stumbling over John Kennedy's "Ich Bin Ein Berliner" phrase and giving the impression that he and his text had met only moments before. A generation renowned for not doing its homework may well have met its leader.

The title of Biden's speech, delivered at the John F. Kennedy School of Government, was "The Right Price, the Right Burden: American Foreign Policy in the 1990s" -- not exactly a modest agenda. As required of a presidential candidate in the John F. Kennedy mode, Biden peppered his speech with the requisite citations: William Butler Yeats, former British foreign secretary Ernest Bevin, Soviet expert Seweryn Bialer (mispronounced), writers Leslie Gelb and Richard Betts, Bishop Desmond Tutu, Harvard professor Stanley Hoffmann, Walt Whitman and, of course, Kennedy. Having assembled that posse, he then rode off to say nothing much.

Not that it mattered. He drew an SRO crowd, and his audience seemed to like what it heard. By reputation, Biden is the Democratic Party's boy orator, and he did nothing at Harvard to put his standing in doubt. Self-confident (if not self-enamored), Biden was both personable and pugnacious. In response to a question, he rued the departure of Gary Hart from the Democratic race: "I would make a better president. . . . I know more about the issues. I would have beaten him if he had stayed in."

But Biden also has a reputation as a politician whose intellect is no match for his glibness. He did nothing at Harvard to bring that into question either. He tackled the difficult question of when the United States should use force in pursuing foreign policy goals. He set out three criteria: (1) Only if our vital interests are threatened. (2) Only if the intervention is "right." (3) Only if the use of force has a "high probability of succeeding."

All of that sounded good, but Biden never bothered to explain his terms. He mentioned Nicaragua as an example of where the Reagan administration had failed to apply those criteria. But these happen to be precisely the criteria the president says he has used. Reagan says Nicaragua is vital, that the fight against an avowedly Marxist regime is "right," and that the effort to topple the Sandinistas would have "a high probability of succeeding" if only Congress would fund the effort.

Similarly, Biden characterized U.S. escalation in the Persian Gulf as reactive, which surely it is, but he did not say what he would do differently if he were president. Several times, he said the containment policy, first enunciated by Harry S Truman, is outmoded. But he never acknowledged that the Reagan administration agrees -- and has set out to roll back communist advances.

Some of what Biden said was good. He lambasted the administration for its amoral South Africa policy. He had the guts, at Harvard yet, to modify John Kennedy's famous call to arms, saying "While we cannot pay any price and bear any burden, we must pay the right price and bear the right burden." Once again, he failed to say what the "right price" or the "right burden" might be.

In essence, Biden enunciated the Doctrine of the Golden Mean. He would do all things in moderation and he would do them right. But if Democrats are to do intellectual battle with the proponents of the Reagan Doctrine, they have to get in close -- talk in detail, provide examples, use today's headlines to make the case for tomorrow's foreign policy. Biden did almost none of that.

Presidential candidates, especially Democrats, seem enamored this year of themes. But themes, while fine, are worthless unless they are thought through with precision. Biden had the themes, all right, but not the precision. Specific situations -- the Persian Gulf, for instance -- need specific solutions. George C. Marshall met that obligation at Harvard 40 years ago. A great man came to a great university and offered a great plan for the economic rehabilitation of Europe. Joe Biden came to Harvard and served up a theme. Call it the Biden Plan. It seemed designed to make other candidates look thoughtful