Probability Thresholds

65 Pages Posted: 24 Jul 2006 Last revised: 24 Feb 2011

See all articles by Jonathan S. Masur

Jonathan S. Masur

University of Chicago - Law School

Date Written: April 4, 2006


Scholars and lower courts have traditionally operated under the belief that cases involving direct tradeoffs between free speech and national security call for the application of straightforward cost-benefit analysis. But the Supreme Court has refused to adhere to this approach, instead deciding difficult liberty-versus-security questions with reference to a “probability threshold” - a doctrinal floor defining how likely a potential threat must be in order to register in the constitutional calculus. This doctrinal innovation has served as a necessary corrective to what would otherwise be the systematic overestimation of speech-based threats driven by the interaction of two factors. First, distinct informational asymmetries favor the government, the putative censor. Second, courts and other lay risk analysts - through the exercise of bounded rationality - tend to overstate very low-probability, highly emotionally salient dangers.

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

JEL Classification: K39

Suggested Citation

Masur, Jonathan S., Probability Thresholds (April 4, 2006). Iowa Law Review, Vol. 92, May 2007, Available at SSRN:

Jonathan S. Masur (Contact Author)

University of Chicago - Law School ( email )

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