Probability Thresholds

Abstract:     
It has become almost received wisdom among scholars and lower courts that the appropriate methodology for deciding difficult cases involving direct tradeoffs between freedom and security is cost-benefit analysis, a straightforward weighing of harms and benefits. But the First Amendment, as interpreted by the Supreme Court, has taken a very different approach. Rather than prescribing a pure balancing of harms and benefits, it instead inserts what this article calls a probability threshold: a lower bound on how likely a potential threat must be in order for that harm to register in the constitutional calculus. If a putative danger is so unlikely that the probability that it will occur does not cross this threshold, courts will simply refuse to weigh it against the benefits that the speech is likely to produce.

This article thus urges a drastic rethinking of the approach that scholars and lower courts have taken to this crucial class of speech-vs.-security cases and attempts to account for such a significant anomaly within such a venerable doctrine. In so doing, it deploys the cognitive insights of behavioral law and economics both positively and normatively. The institutional relationship between the courts and the executive, and indeed the very nature of low-probability dangers, render such a threshold a necessary corrective to what would otherwise be systematic overestimation of speech-borne perils. More generally, it is likely that intuitive conceptions of behavioral economics and cognitive science - intuitions that predate much of the modern literature on these topics - have left their mark across a variety of areas of public and private law. Further research holds the potential to reveal and illuminate these cognitive echoes.

Keywords: first amendment, probability, clear and present, behavioral law and economics, availability heuristic, cost-benefit, balancing, cognitive

JEL Classifications: K39

Accepted Paper Series