Montesquieu's Mistakes and the True Meaning of Separation

Abstract

In The Spirit of the Laws, Montesquieu concluded that a constitution of liberty could best be achieved, and had been achieved in Britain, by assigning three essentially different governmental activities to different actors. He was wrong. His mistaken conclusion rested on two errors. First, Montesquieu thought that the primary exercise of powers could durably be divided only where those powers differed in kind. Second, Montesquieu failed to recognize the lawmaking character of executive and judicial exposition of existing law. This article analyzes implications of Montesquieu’s mistakes for modern claims, both in Britain and in the United States, that liberty and the rule of law are promoted by separating power in certain contexts. In particular, this article questions the British Government’s recent claim that the values underlying separation-of-powers theory call for removing ultimate appellate jurisdiction from the House of Lords. It also traces Montesquieu’s influence on the American founders’ attempt to separate power along essentialist lines, and considers some sub-optimal consequences of that attempt, including the non-delegation quandary and the emergence of an unchecked judicial lawmaker.