He got out quickly and cleanly after a singular show of the stiff upper lip. Maybe he achieved moral resurrection and the right to fight another year. But the passion has been torn to tatters. Events now move in a different direction. The chances are that the Kennedy parenthesis in national affairs has been closed -- but this country has lost one more thing that made it not like other countries.

For weeks, Sen. Kennedy bore alone a dreadful punishment. Carterites crowed that he was "unelectable." Other Democrats with ideas about a third man labeled him a "spoiler." Many in the press and television -- fancying themselves custodians of the true perception -- kept insisting the game was over in tones that implied that, by still playing, he was, somehow, breaking the rules.

Friends and family went off on vacation, shaking their heads in bewilderment. One relative very close to the senator volunteered the view that his behavior was "metaphysical" -- a term that signifies, in the Kennedy lexicon, what passeth understanding.

Pop psychology, to be sure, provides a ready explanation. The senator was a late-born child, 15 years younger than his brother John, seven years younger than his brother Robert. He couldn't easily compete, but he had an engaging nature and he kept testing his appeal by breaking the family code of achievement. Hence a host of awfuls reaching their apex in Chappaquiddick.

Hence, too, a willingness to take punishment as a kind of expiation, and a strong gift for survival. If all that is right, then the senator has done it again. He paid the price for a sorry campaign, but now emerges, Chappaquiddick behind him, as the conscience of his party. The road is cleared for 1984 and beyond. "The dream," as he said in the windup of his speech Tuesday night, "shall never die."

Sober appraisal, however, yields a different prospect. There is something deeply senatorial about Edward Kennedy. In mind, as in looks, he lacks tautness. He is not mean but neither is he keen. He did not work out a clear strategy when he began his presidential campaign. Nor -- although it seems to have worked out all right -- did he plot an ending.

His policies reflect his qualities. On inflation, he probably comes closer to being right and he alone -- has the courage to go after prices and wages.

But has his well-founded concern with the biggest issue been introduced to any of his other policies? Certainly not to an energy program that depends on rationing gasoline and abusing the oil companies. Nor to a jobs program that would spend $12 billion on a federal employment package. Put those together with proposals for unilaterally freezing nuclear weapons development and ending draft registration and financing abortions out of federal funds, and there emerges a factional approach, limited ideologically to the purest of liberals. Regionally, it finds its confines in the states of the Northeast and California. Most important, there is the age boundary.

Half the Americans eligible to vote in the presidential election -- some 75 million people -- do not exercise the franchise. Most are under the age of 30. Jimmy Carter does not engage them. Neither does Ronald Reagan.

But does Edward Kennedy? The evidence goes against it. During the primaries, the senator won chiefly in the states where there was an old-fashioned Kennedy presence -- a large number of Catholic voters and a strong hold by the labor unions. He barely stirred the torpor of the young voters.

The fact is that the Kennedy mystique represents a waning force. The young have no memory of Jack Kennedy, and only the dimmest recollection of Bob. The hope they expressed vanishes over the horizon of time. Their battle cries evoke less and less response -- which is one reason the senator, even in parts of his fine speech Tuesday night, sounded so much like a parody.

Inevitably, the majority of the future will find heroes of its own. Probably they are figures only now coming onto the national stage. Almost certainly they will be different in tone and spirit and stance from Kennedy.

Some people will undoubtedly find in the sinking of the Kennedy star a cause to rejoice. It is certainly true that the Kennedy mystique has been a freakish force, distorting national politics by creating false hopes and unreal hates.

For my own part, however, the closing of the Kennedy parenthesis occasions sadness. The possibility of a return to Kennedy rule always seemed to me a reserve asset, a sign of resiliency, an augury of hope in a time of despair. That hope now fades, along with many other blessings that made America what it was, and is ceasing to be.