Separation of Powers
In Summary
“There would be an end of every thing, were the same man, or the same body, whether of the nobles or of the people, to exercise those three powers, that of enacting laws, that of executing the public resolutions, and of trying the causes of individuals.”
Montesquieu
The Spirit of the Laws, Book XI
The delegation of executive, legislative, and judicial powers among three separate branches of government is one mechanism by which the framers hoped to prevent the growth of a despotic ruler in the United States. Articles I, II, and III lay out the powers of each branch and create procedures for interaction between branches. Despite the framers efforts, the branches have not always stayed within their bounds. The sources below explain the principle of separation of powers, how the U.S. Constitution embodies the principle, and instances in history when one branch or another has overstepped its Constitutional bounds.
JMC Resources

Constitutional Articles, Amendments, and Debates
The first three articles of the Constitution define the powers and structure of the three branches of the U.S. government. The enumeration of specific powers in these articles is one way the Constitution ensures power is not consolidated in any one branch. In some cases, the Constitution describes specific scenarios in which different branches work together to perform one governmental action, such as Senate approval of certain Presidential appointments. Each article is linked below. Pay close attention to Article 1, Section 7 and 8, Article 2, Section 2, and Article 3, Section 2.
Each of the Amendments below was proposed and ratified after a controversy involving a perceived abuse of power by one branch. The Eleventh Amendment reins in the power of the Supreme Court, the Twenty-Second Amendment addresses concerns about the growing power of the Presidency, and the Twenty-Fifth Amendment establishes procedures for addressing the replacement and removal of the President.
A common concern among Anti-Federalists after the Constitutional Convention was that the three branches of government were not sufficiently separated. Cato and Brutus express concerns about power being too easily consolidated and abused by the executive and judiciary branches. Publius on the other hand, famously argues in Federalist Paper, No. 51 that the Constitution creates the proper degree of separation between the branches while still making each somewhat dependent on the others. He addresses more specific Anti-Federalist concerns in the papers below.
On the Executive
Cato IV (sometimes Anti-Federalist No. 67), 1787
Federalist Papers, No. 69, 1788
Federalist Papers, No. 77, 1788
On the Judiciary
Federalist Papers, No. 78, 1788

Presidential Speeches
The texts below justify an action taken or suggested by a president that could be interpreted as beyond the enumerated powers in Article II of the Constitution. Each text includes an introduction from Professor David Ramsey that calls attention to the perceived infringement by the president on another branch of the government.
Andrew Jackson, Veto of the Bank Bill (excerpt), 1832
Abraham Lincoln, Special Session Message (excerpt), 1861
Franklin Delano Roosevelt, “Court-Packing” Address (excerpt), 1937

Supreme Court Cases
The opinion excerpted here from Cooper v. Aaron (1958) establishes that “the federal judiciary is supreme in the exposition of the law of the Constitution.” This claim of judicial supremacy, which Brutus expresses concerns about in 1788, goes against President Jackson’s argument in his veto message. The opinion references Marbury v. Madison (1803) to justify the claim that the Supreme Court’s ruling on a constitutional issue is final.
The dissenting opinion in Baker v. Carr (1962) warns against judicial action on “political questions” historically left to the legislative and executive branches. Justices Frankfurter and Harlan believe that the Supreme Court’s role is only to resolve Constitutional questions and should be kept out of political debates.

Origins of Separation of Powers
In 2017, JMC Partner Professor John Zumbrunnen taught a yearlong program at the University of Wisconsin-Madison on the separation of powers. Each section includes primary source documents, background information, and discussion questions by Professor Zumbrunnen. This comprehensive resource includes writings from Plato and Aristotle to Locke and Hobbes to Federalists and Anti-Federalists. The readings provide a broad overview of the philosophical concept of separation of powers and its practical application in the United States government.
American Democracy Educator’s Forum 2017-18
One section of particular importance is the excerpt from Montesquieu’s The Spirit of the Laws. Montesquieu examines the constitution of England and describes the three kinds of power in each state: “legislative power, executive power over the things depending on the right of nations, and executive power over the things depending on civil right.” For the full section from which Professor Zumbrunnen pulls this excerpt, see Book 11 from The Spirit of the Laws.
Other Resources
Separation of Powers with Checks and Balances
Bill of Rights Institute
Balancing Three Branches at Once: Our System of Checks and Balances
NEH EDSITEment!
Separation of Powers
National Constitution Center