Legal systems do not usually abandon liberty all at once. They lose it by removing the small frictions that keep power divided: the distance between the official who states the rule, the official who finds the facts, and the official who commands the force. This article traces that danger across three older institutions—the Roman magistracy, the Spanish Inquisition, and the English Star Chamber—and then follows the same structural logic into the modern American administrative state and Israel’s recent constitutional crisis. Across these settings, the danger appears in different clothes but follows the same institutional pattern: efficiency, emergency, or expertise becomes the reason to fuse powers that law had once worked to separate. Whenever legal systems treat separation as inefficiency, and friction as a technical obstacle to be overcome, they begin to rebuild the very architecture that constitutional law exists to prevent. The enduring question is therefore not whether officials act in good faith, but whether the structure they inhabit makes arbitrary judgment difficult even when they do.