Blogger Steve Bunche says this “Dennis the Menace” gag actually ran in newspapers in 1970. I believe it. (Click the image for a larger look.)
UPDATE: (12/05/08): A participant at an online comics forum wrote last night: “True. The strip did run in many papers, although some editors pulled it. Others ran apologies the next day.
“Reactionary Whites were offended by the mere presence of the black boy, and Blacks were offended because he was drawn in the old stereotypical manner. The incident is documented in Mort Walker's book ‘Backstage at the Strips.’ ”