According to the latest Census, a majority of Americans - 57.5 percent, to be exact - are under 40 years of age. Thus, most Americans have no personal memory of that fateful day of Nov. 22, 1963, when President Kennedy was assassinated. For this generation, names like Lee Harvey Oswald and the Warren Commission are merely trivia quiz questions.
John Kennedy is beginning to slip into our troubled history, like Lincoln. He exists in a variety of books, TV shows, and movies; some, like Oliver Stone's movie, purveying wild assassination theories.
In this anniversary week, there has been much in the media about the drama of Kennedy, but less about the legacy of Kennedy. As one of the Kennedy generation (he'd have been 86, almost exactly my age), I think of 40 years as a good time to reflect on Kennedy's more enduring contributions to our national life:
First of all, the pursuit of peace, even in the face of Soviet provocation, inaugurating a generation of détente and arms control with the Nuclear Test Ban Treaty.
Then, the "equal rights" revolution, laying the groundwork for the Civil Rights Act that President Johnson achieved.
Then, the "ask not" summons to volunteerism and sacrifice among young people, its monuments being the Peace Corps and the contemporary AmeriCorps.
Then, the space program and the challenge to send a man to the moon within a decade - which culminated on President Nixon's watch.
Finally, the sense of optimism that Kennedy conveyed about America's future - not just in slogans like "New Frontier" and "getting the country moving again," but in getting a start on fashioning a national agenda.
Forty years later it may be time to remind those who came after of what Kennedy left behind.
• Daniel Schorr is a senior news analyst at National Public Radio.