Jim and Jonah, I was born within a few weeks of President Obama, and while our upbringings were quite different, the historical events that I can remember are probably not that much different from his.

The earliest one I can recall was LBJ’s announcement in the spring of 1968 that he would not run for reelection. As far as I was concerned, he had been president since the dawn of time, so I knew this was a momentous occasion. I remember Robert Kennedy’s assassination (though I did not learn until years later that he was a senator from my state), but not Martin Luther King’s. And I remember Richard Nixon’s election in November 1968, which my family listened to on the Voice of America from our temporary home overseas, but nothing about that year’s presidential campaigns or conventions, or the Tet Offensive, or the campus riots . . . 1968 was so momentous, start to finish, that I sometimes think somebody slightly older than me, who can remember the whole year, must be the equivalent of a decade more experienced.

I will say that the Vietnam War, like LBJ, seemed to have been around forever when I was growing up, and we heard a lot about it for years before the “peace” agreement of 1973 — though, oddly, no one bothered to explain to me that we were fighting a Communist regime; I got the clear impression that we had sent troops to Vietnam just to be ornery. Something tells me that young Barack Obama got the same impression, and never lost it. (For what it’s worth, the general view in Columbia’s history department when he and I were both enrolled there was that the Viet Cong were not Communists but nationalists, and the Americans were too dumb to understand that the Vietnamese people simply wanted a country of their own.)

Anyway, it is of course true that lumping Bush 43 and Bill Clinton together with Barack Obama as “Baby Boomers” makes no sense except from the standpoint of birth-rate statistics. To make that conglomeration work, you would have to cut out at least a couple of verses from “We Didn’t Start the Fire” . . .