Slippery Slope Arguments in History: The Supreme Court in the Flag Salute Case
Camel (A) sticks his nose under the tent (B), which collapses, driving the thin end of the wedge (C) to cause monkey to open floodgates (D), letting water flow down the slippery slope (E) to irrigate acorn (F) which grows into oak (G). [Illustration by Eric Kim, from my idea.]
From Justice Jackson's majority opinion in W. Va. State Bd. of Educ. v. Barnette (1943):
As first and moderate methods to attain unity have failed, those bent on its accomplishment must resort to an ever-increasing severity…. Those who begin coercive elimination of dissent soon find themselves exterminating dissenters…. [T]he First Amendment to our Constitution was designed to avoid these ends by avoiding these beginnings.