“It’s only meant to be persuasive, not binding.” Thus runs, mantra-like, our blanket, disarming defense—against plausible objections—of judicial invocations of foreign law in U.S. constitutional cases. Professor Youngjae Lee’s manifest urge to burst this bubble feels entirely right to me.

I further like the boldness of Professor Lee’s strategy. The data presented by Justice Kennedy’s opinion for the Court in Roper v. Simmons would seem to be special in purporting to show a literally unanimous, worldwide rejection of the juvenile death penalty outside of the United States. If even such a total worldwide consensus could be shown to lack instructiveness when applying the Eighth Amendment’s Punishments Clause, then surely—I take Professor Lee to be suggesting—no divided, brute nose-count of foreign law outcomes could be thought instructive, at least in the Punishments Clause context. Professor Lee thus sets for himself the task of establishing—against our predictable, strong intuitions—the negligible epistemic value, in this context, of even an external unanimity (let alone a mere majority) of outcomes. That task is daunting because, as I shall explain, data showing a unanimous worldwide rejection of the death penalty for juveniles seem especially resilient to challenges to instructiveness such as those marshaled by Professor Lee. (I deal here only with the central issue raised by Professor Lee’s article, that of the persuasive weight, if any, carried by an external consensus on punishment calibration, in a Roper-like context of U.S. Punishments Clause adjudication.)