After a series of highly publicized incidents of police violence, a growing number of courts, scholars, and politicians have demanded the abolition of qualified immunity. The doctrine requires courts to dismiss damages actions against officials for violating the plaintiff’s constitutional rights unless a reasonable officer would have known that the right was “clearly established.” Scholars argue that the doctrine forecloses compensation and vindication for victims and stands in the way of deterring constitutional violations in the future.

One argument against qualified immunity has relied on empirical evidence to challenge what scholars take to be the main justification for qualified immunity: it prevents the threat of constitutional liability from over-deterring effective law enforcement. Yet the Supreme Court of the United States has always offered another rationale for the doctrine: it would be unfair to hold officers liable without sufficient notice that their conduct was unconstitutional. Unlike the overdeterrence rationale, scholars have almost entirely ignored the fair notice rationale for qualified immunity.

This Article assesses the extent to which the fair notice rationale supports the current doctrine of qualified immunity. It does so by exploring the limits of the jurisprudential principle of prospectivity, which holds that the law must ordinarily apply only prospectively. To approximate the rule of law and to treat subjects with equal dignity, the law must be capable of guiding conduct. The principle of prospectivity obviously applies to retroactive legislation. This Article makes the novel case that unpredictable adjudications also fail to provide such guidance and that they are especially unfair when they impose retroactive moral condemnation. Constitutional liability is often highly unpredictable, seemingly at odds with prior legal duties, and, unlike most tort liability, expresses the community’s moral censure.

Based on this fresh analysis of retroactive adjudication, this Article argues that concerns about fair notice to officials do support a form of qualified immunity, but one that is much more modest than the current doctrine. It supports immunity where an officer could not have reasonably foreseen constitutional liability or public condemnation, but, importantly, not when an officer acted in bad faith, violated a criminal law, or violated a constitutional rule with an underlying rationale that applies to the officer’s conduct. Taking the fair notice rationale seriously provides a principled roadmap for reforming qualified immunity.