The Separation of Powers in the US Constitution

The doctrine of the separation of powers, developed in its modern form by Montesquieu in The Spirit of the Laws (1748), was given its most successful practical application in the United States Constitution. The framers of the Constitution drew directly on Montesquieu’s arguments, and the American system of government was explicitly designed to embody the principles of the separation of powers. This article examines the application of the separation of powers in the US Constitution, including the three branches, the system of checks and balances, and the contemporary significance of the doctrine.

The Background

The American founders were deeply influenced by Montesquieu’s account of the English constitution, and they believed that the proper organization of the new American republic required the separation of the powers of government into distinct branches.

The system of separation of powers was not the only model that the founders considered. The British system, with its mixture of monarchy, aristocracy, and democracy, was one model. The state constitutions, with their various experiments in separation of powers, were another. The Continental Congress, with its committee structure, was yet another.

The system that the founders eventually adopted was a mixture of these various models, but it was based, above all, on the principles of the separation of powers developed by Montesquieu. The federal system established by the Constitution, with its three branches and its system of checks and balances, was the most ambitious attempt to apply the principles of the separation of powers that had ever been made.

The Three Branches

The Constitution establishes three branches of government, each with its own powers and each subject to the checks of the others.

The Legislative Branch, consisting of the Senate and the House of Representatives, exercises the legislative power. The legislative power is the power to make laws, and to appropriate the money necessary to carry out the operations of the government. The Congress is elected by the people, with the members of the House of Representatives elected for two-year terms and the members of the Senate elected for six-year terms.

The Executive Branch, headed by the President, exercises the executive power. The executive power is the power to execute the laws, to command the armed forces, to conduct foreign affairs, and to appoint the principal officers of the government. The President is elected for a four-year term by an electoral college, with each state having a number of electoral votes equal to its total representation in Congress.

The Judicial Branch, headed by the Supreme Court, exercises the judicial power. The judicial power is the power to interpret the laws and the Constitution, and to apply the laws to particular cases. The justices of the Supreme Court are appointed by the President with the consent of the Senate, and they hold their offices during good behavior.

The System of Checks and Balances

The system of checks and balances established by the Constitution ensures that no single branch can exercise arbitrary power over the others.

The legislative branch can check the executive branch through the power to pass laws, the power to appropriate money, the power to confirm presidential appointments, and the power to impeach and remove the President. The executive branch can check the legislative branch through the power to veto legislation, the power to recommend legislation to Congress, and the power to convene and adjourn Congress under certain circumstances. The judicial branch can check the legislative and executive branches through the power of judicial review — the power to declare laws and executive actions unconstitutional.

The system of checks and balances is designed to prevent the concentration of power in any one branch, and to ensure that the government operates through the cooperation of all three branches. The system is a complex one, and it requires constant negotiation and compromise among the branches.

The Federalist Defence

The most systematic theoretical defense of the American system of separation of powers was provided by the Federalist Papers, written by Alexander Hamilton, James Madison, and John Jay in 1787–1788. The Federalist Papers are among the great works of American political thought, and they provide a detailed defense of the principles of the Constitution.

Madison’s contribution to the Federalist defence of the Constitution, in particular, drew on Montesquieu’s arguments and developed them. Madison argued that the separation of powers was necessary to control the “violence of faction” — the tendency of human beings to form groups with interests opposed to the rights of other groups or to the common good. The system of checks and balances established by the Constitution was, in Madison’s view, the most effective institutional mechanism for protecting the rights of minorities against the tyranny of the majority. For the broader account of the doctrine and its critics, see The Separation of Powers.

The Contemporary Significance

The American system of separation of powers has been widely imitated in the constitutional systems of other countries, and it has become a basic feature of modern constitutional government. The contemporary debate about the proper organization of the American government is, a continuation of the debate that the founders began.

The contemporary challenges to the American system include the proper balance between the three branches, the proper scope of judicial review, the proper response to the increasing power of the executive branch, and the proper management of the relationship between the federal government and the state governments. These challenges are part of the broader debate about the proper foundations of constitutional government, and the engagement with them is, a continuation of the engagement that the founders began in the Federalist Papers.

Further Reading

• The Stanford Encyclopedia of Philosophy (plato.stanford.edu), relevant entry
• Mark Goldie & Robert Wokler, eds., The Cambridge History of Eighteenth-Century Political Thought (2006)
• Terence Ball, Reappraising Political Theory (1995)