Almost every lawyer has heard the commonplace that one legal decision or another is “a ticket good for one day only.” This metaphor captures the idea that a decision lacks precedential value: it is here today, but gone before tomorrow’s train. The metaphor is powerful because the idea of a one-day-only precedent is almost always viewed with derision. A legal principle, if sound, is expected to survive the day it was decided and to last far into the future – perhaps even forever. The “one-day ticket” metaphor has itself passed that test, persisting in American legal culture for nearly 80 years. Over its long career, the expression has been put to a variety of uses by jurists of every ideological bent, and each usage has its own lessons and ironies.