The Supreme Court's recent decision in Pearson v. Callahan marked a turning point in a judicial experiment concerning § 1983 constitutional litigation, which began in 2001 with Saucier v. Katz. The experiment involved the doctrine of qualified immunity, an immunity from suit extended to state and local government officials (and to federal officials in Bivens actions) in § 1983 actions for monetary relief where it would not be "clear to a reasonable officer that his conduct was unlawful in the situation he confronted."

A court deciding a § 1983 action in which the defendant pleads qualified immunity faces two possible questions: (1) whether a constitutional right of the plaintiff was violated; and (2) whether that right was "clearly established" at the time the conduct occurred. If the court answers the first question “no,” the defendant prevails because the plaintiff has failed to successfully allege a constitutional violation. If the court answers the second question “no,” the defendant is entitled to qualified immunity, barring the plaintiff’s recovery. The question at the heart of the line of cases leading to Pearson is whether a court must confront the constitutional question regardless of the outcome of the “clearly established” qualified immunity prong, or whether a court may skip the substantive constitutional issue altogether when the answer to the “clearly established” prong supports granting qualified immunity.

The stakes are high because the difference between mandatory or discretionary sequencing may bear on the frequency with which courts address substantive constitutional rights questions, which in turn impacts the “rate” at which constitutional rights are “clearly established” through precedents. While the Supreme Court’s jurisprudence has spanned the spectrum from providing no guidance about sequencing, to suggesting it, to requiring it, and after Pearson, again to only suggesting it, there have been until recently no empirical studies that examined the relationship between the Supreme Court’s position on the qualified immunity sequencing issue and the behavior of lower courts resolving § 1983 claims...