Doonesbury by Garry Trudeau for September 02, 1971
Transcript:
Mark: How'd you enjoy ROTC camp, B.D.? B.D.: It was great! Mark: really? I don't think I could ever join ROTC. I'm going to be a C.O....I just don't believe in violence. B.D.: How do you know? Have you ever been violent? Have you ever attacked a man with a bayonet? Huh? Don't knock it until you've tried it!
Is this the first example of a character turning to the readership in the last panel?