Marge, campaigning for the "Yokel Objectivist" vote, tells Cletus that she objects to darn revenuers. Cletus, holding a copy of "The Fountainhead" (by Ayn Rand, who created the philosophy she called Objectivism) says that Marge is like John Galt. John Galt is a character in "Atlas Shrugged", a different book also by Ayn Rand. Maybe Cletus didn't have a copy of "Atlas Shrugged" handy; the corresponding character in "The Fountainhead" would be Howard Roark.