The mice of the Nutmeg residence have lost the War of Feline Aggression. Mrs. Nutmeg will miss those pesky, patriotic pests (awesome alliteration, asshole), because she's bleeding stupid enough to assume that the mice are carrying around a replica of the original American flag. Those mutant rats are crafty, but not so mentally advanced as to fool the true patriot in this strip. Heathcliff knows the score: the flag had 13 stars, not 7.
Still, I'm curious as to what "Battle Hymn of the Mousepublic" sounds like.