Checks and Balances

Separating powers alone would not prevent one branch from overrunning the others, Madison argued, so each needed the means and motive to resist. In Federalist No. 51 he wrote that ambition must be made to counteract ambition. The Constitution therefore gives every branch specific weapons against the others, so that major actions require the cooperation, or at least the acquiescence, of more than one.

Congress checks the President by overriding vetoes, controlling appropriations, confirming or rejecting nominees, approving treaties, investigating, and impeaching and removing officials. It checks the courts by setting their jurisdiction and size, confirming judges, and impeaching them. The President checks Congress through the veto and checks the courts through judicial nominations and the pardon power. The courts check both through judicial review, striking down laws and executive actions that violate the Constitution. The two chambers of Congress also check each other, since both must pass every law.

The system works only when officials defend their institution's prerogatives. Political scientists have observed that loyalty to party now often outweighs loyalty to branch, so that a Congress controlled by the President's party may decline to use its tools while a Congress controlled by the opposition uses them aggressively. Debates over executive power, unfilled oversight, and the courts' role in reviewing presidential action are in large part debates over whether the checks are still functioning as designed.