Superman Smashes the Klan is loosely based on a 16-part episode story-arc, "Clan of the Fiery Cross", from the radio serial Adventures of Superman which ran from June to July 1946.[3][6][8] In the radio serial, "Superman exposed Ku Klux Klan codewords, rituals, and its bigotry—all based on intel collected by activist Stetson Kennedy—before a national audience. The show damaged the group's reputation and led to a steep decline in membership from which the KKK never recovered".[6]