I didn’t read or watch every observation of the anniversary of John F. Kennedy’s assassination (who could?)  but the ones I did gave short shrift to his signal accomplishment — saving the world from a nuclear holocaust.

His cool restraint during the 1962 Cuban Missile Crisis — resisting many advisers who were calling for bombing Soviet missile sites in Cuba — ought to earn him the top-of-the-heap public approval ratings he enjoys (90 percent in a CNN poll).

I doubt the ratings are based on that, though. His celebrated grace, glamour, wit, eloquence, inspiration of a generation to public service, his (belated) support for civil rights, the Camelot myth created by his widow — and, above all, his martyrdom — most likely are the major factors.

Historians rate him lower than the public does. If you look at the excellent Wikipedia site, Historical Rankings of Presidents of the United States, he rates in the middle-upper tier in a dozen surveys of historians — 14th in a 2002 Sienna College survey.

Among the commentaries leading up to last week’s commemorations, some were withering. The Los Angeles Times columnist Doyle McManus noted that a 1988 survey of historians rated Kennedy the most overrated figure in American history. McManus quoted his biographer, Robert Dalek, as saying “most historians think of him as an average or even below-average president. He never got any of his legislative initiatives passed. He was the architect of a failed policy in Cuba. It’s possible to look at his record and see real misery.”

In The Washington Post, ace columnist Robert Samuelson declared, “He was not a great president. He was somewhere between middling and mediocre.” Samuelson wrongly blames Kennedy’s tax cuts, enacted after his death, for launching the Great Inflation of the late 1960s and 1970s. Actually, that was Lyndon Johnson’s doing.

Kennedy did get the war in Vietnam started, and historians at the University of Virginia’s Miller Center who conduct extensive oral histories of presidencies have told me that the balance of the evidence strongly suggests he would have escalated the war, not withdrawn, as his admirers aver.

Also on the downside, of course: his compulsive womanizing, his concealment of his Addison’s disease and the dangerous cocktail of drugs he used to treat it, and his efforts to assassinate Fidel Castro.

But, against all this, we have the 13 days of October 1962, when the Soviets were discovered installing nuclear missiles in Cuba that could hit most of the United States. When called on it, they speeded up the installation process. They shot down an American U2 spy plane. Kennedy created the so-called ExComm to consider what to do.

The Joint Chiefs of Staff wanted to bomb and invade Cuba, which well could have triggered World War III. Most of the civilian members of the ExComm — CIA Director John McCone, Treasury Secretary Douglas Dillon, Secretary of State Dean Rusk, ex-Secretary of State Dean Acheson and, especially, Vice President Johnson — favored military action, too.

When congressional leaders were called in, Johnson, according to biographer Robert Caro, stayed silent as one leader after another insisted on war, including future Vietnam dove Sen. William Fulbright, D-Ark., chairman of the Senate Foreign Relations Committee.

Kennedy and his brother, Bobby, however, kept cool. Kennedy instituted a naval “quarantine” instead of an attack, communicated with Nikita Khrushchev, repeatedly gave him time and opportunities to stand down, and ultimately reached a secret deal to remove obsolete U.S. missiles from Turkey in exchange for full withdrawal of the Soviet missiles from Cuba.

The United States and Soviet Union at several points came within minutes of nuclear confrontation and Kennedy bided for time while Johnson, in particular, was saying “showing weakness to a mad dog is always wrong.”

But if your good judgment saves the world from nuclear war, I say, you deserve high marks.