Precedentism: What the Past Can Prove, With a Judge and Without One

A child refused something rarely reaches for a theory of fairness. She reaches for a fact: her brother did this exact thing, at this exact age, and nothing bad happened. That small, almost involuntary move, formalized and given a Latin name, is one of the engines of the entire common-law tradition, and, in a far less disciplined form, one of the engines of how governments and movements decide what a present event permits. This essay follows the move under two different conditions. Inside a courtroom, a cited precedent gets tested, distinguished, or overruled by an institution built to notice when an extrapolation from it has gone wrong. Outside a courtroom — in a diplomat's argument that an intervention is permissible because a past one went unpunished, or a movement's claim that a cause survives its murdered leader — the same move operates with no institution empowered to settle whether it is any good. Two events from early 2026, the killing of Iran's Supreme Leader and the capture of Venezuela's president, are already being argued over as precedent, by name, by international lawyers and an actual American court. Tested against Popper's critique of historicism, the two forms come out differently for a specific reason, and the essay closes by turning the same test on this corpus's own practice, where the same distinction holds inside its own pages.