Artists: Time of the Assassins

Cartooning, says Robert Osborn, "is a nice, pleasant, enjoyable profession." Presumably this is because, before the bile can accumulate, Osborn has worked it off in a few devastating slashes of pen on paper. He got the stored-up frustrations and anger of World War II off his chest with a 1946 book War Is No Damn Good!; his 1960 book The Vulgarians took a snickersnee to the mediocrity of mass society.

But what happens when a catastrophe overwhelms the cartoonist's ability to poniard a convenient victim on pen point? In Osborn's case, the assassination of John F. Kennedy left...