Separation of Powers

The framers believed that concentrating all power in one set of hands was the definition of tyranny. Drawing on Montesquieu's The Spirit of the Laws of 1748 and on the experience of state governments, they wrote a Constitution whose first three articles each vest a distinct power in a distinct branch: all legislative powers in Congress, the executive power in a President, and the judicial power in the Supreme Court and lower courts Congress creates. The Incompatibility Clause bars members of Congress from holding executive office at the same time, a sharp break from parliamentary systems.

The separation is not absolute. James Madison explained in Federalist No. 47 that the branches must be connected enough to give each a constitutional check on the others, which is why the President signs or vetoes laws, the Senate confirms appointments, and courts review both. The Supreme Court enforces the boundaries in disputes over which branch may act. It struck down Truman's seizure of steel mills in Youngstown in 1952, the legislative veto in INS v. Chadha in 1983, and the line-item veto in 1998, and in a series of recent cases it has limited Congress's ability to insulate executive officials from presidential control.

Modern government strains the design. Agencies write rules with the force of law, enforce them, and adjudicate disputes, combining functions the framers separated. Presidents act through executive orders and emergencies when Congress is gridlocked, and Congress often delegates broad authority rather than legislating detail. Debates about the administrative state, war powers, and presidential removal power are, at bottom, arguments about how strictly the separation of powers should be read.