If a court determines that a law with disparate impacts had an impermissible purpose, should that influence the review of subsequent similar legislation? I argue that the answer is yes, not because it is necessary to get the review of the subsequent laws right—although it may be—but because it will deter legislatures from acting on impermissible purposes in the first place. I analyze the strategic interaction between a legislature and a court, where the legislature’s motives for passing laws with disparate impacts influence the court’s judgment about whether those laws should be upheld. The court prefers to uphold an unequal law if there is a legitimate purpose for the inequality but not if the legislature is motivated by animus. If this “game” between the legislature and court is played once, then the court cannot deter laws motivated by animus without also deterring laws with legitimate purposes. But if the game is repeated, the court can selectively deter only those laws motivated by animus if the taint is inherited by subsequent legal enactments for some length of time. By appropriately choosing the length of that time, a court can choose the “end of animus” to prevent it from ever beginning.

Andrew Hayashi, The End and the Beginning of Animus, 74 Alabama Law Review 697–723 (2023).