Sociologists are beginning to think that the sexual revolution of recent years has a wider significance than merely who sleeps with whom. Certainly, in Morrison's completely unambiguous lyrics, it seems to be part of a wider scene where all the comfortable assumptions are challenged.

"We want the world and we want it now," he yells, and audiences have been known to join in the chorus. But the atmosphere is something else again from the "We Shall Overcome" cosiness that they have made of Pete Seeger's great music.

LBJ has been known to sing along with "Overcome," but I don't fancy he'll be able to mouth the words of Morrison's "The Unknown Soldier," an apocalyptic piece which seems to sum up the Vietnam-nourished violence at the centre of American life.

And when Jim screams "You got the guns, but we got the numbers," protest enters a new dimension, more...