Separation of Powers and Checks and Balances
The Constitution does not create a government and then hand it power. It divides power into three portions, gives each portion to a different institution, and then makes each institution partly dependent on the other two. The division is called separation of powers. The particular tools each branch holds over the others are called checks and balances.
Neither phrase appears in the document. What appears instead is more useful to read: three articles that open with three carefully worded grants, followed by page after page describing the places where those grants deliberately overlap.
Three Articles, Three Grants
Article I opens: “All legislative Powers herein granted shall be vested in a Congress of the United States.” Article II opens: “The executive Power shall be vested in a President of the United States of America.” Article III opens: “The judicial Power of the United States, shall be vested in one supreme Court, and in such inferior Courts as the Congress may from time to time ordain and establish.”
Set those three sentences beside each other and small differences start to matter. Article I’s grant carries two words the others lack, “herein granted,” and Section 8 then lists what Congress may do. Article III leaves the entire lower federal court system to Congress, which is why the number of district courts, the boundaries of the circuits, and even the number of seats on the Supreme Court are fixed by ordinary statute rather than by the Constitution.
Length tells you something too. Article I is longer than Articles II and III combined. The lawmaking body was described first and in the most detail, and its powers were listed one by one instead of granted in general terms. You can see this quickly in the Constitution Annotated, the Library of Congress edition that prints the text with explanatory notes.
The branches are kept separate in their membership as well. Article I, Section 6 bars anyone holding a federal office from sitting in either house of Congress at the same time. Unlike a parliamentary system, the executive here is not drawn from the legislature and cannot sit in it.
The Checks, One at a Time
Each branch holds specific instruments that reach into the work of the others. They are worth learning individually, because most arguments about the structure of American government turn out to be arguments about one of them.
The veto and the override
Article I, Section 7 requires every bill passed by both houses to be presented to the President, who may sign it or return it with objections. A returned bill still becomes law if two-thirds of each house votes for it again. If the President neither signs nor returns a bill within ten days, Sundays excepted, while Congress sits, it becomes law without a signature. If Congress adjourns and so prevents its return, it does not.
Advice and consent
Article II, Section 2 gives the President power to make treaties “provided two thirds of the Senators present concur,” and to nominate ambassadors, Supreme Court justices, and other officers of the United States “by and with the Advice and Consent of the Senate.” The nomination belongs to the President; the appointment is not complete without the Senate. The chamber’s own account of how this developed appears in its origins and foundations materials.
Impeachment and removal
The House holds “the sole Power of Impeachment” under Article I, Section 2, and the Senate holds “the sole Power to try all Impeachments” under Article I, Section 3. Conviction requires two-thirds of the members present. When a President is tried, the Chief Justice presides. Judgment reaches no further than removal from office and disqualification from holding office again, and a convicted party remains liable to ordinary prosecution in the courts.
The power of the purse
Article I, Section 9 states that “No Money shall be drawn from the Treasury, but in Consequence of Appropriations made by Law.” Every dollar the executive branch spends must first be appropriated by Congress. Bills for raising revenue must originate in the House, and appropriations for the army are limited to two years at a time. The House describes its own role in The House Explained.
An independent judiciary
Article III protects judges rather than arming them. Federal judges hold their offices “during good Behaviour,” and their compensation may not be reduced while they serve. The better-known judicial check, the authority to decline to apply a statute a court finds unconstitutional, is nowhere stated in the text. It was established in practice, and it is described on our page about judicial review.
Why the Design Assumes Conflict
During the ratification debate, the essay published as Federalist No. 51 gave the clearest statement of the reasoning behind all of this. Its argument is not that officeholders will be virtuous. It is that they will be interested, and that the interest of the person can be tied to the constitutional rights of the place: “Ambition must be made to counteract ambition.”
If men were angels, no government would be necessary. If angels were to govern men, neither external nor internal controls on government would be necessary.
Read that way, friction between the branches is not evidence that the system is failing. It is the mechanism working as designed. The Library of Congress maintains a research guide to the Federalist essays with full texts and publication history.
Separation Is Not Isolation
The branches were never sealed off from one another. The President signs or vetoes legislation, so the executive has a hand in lawmaking. The Senate confirms judges, so the legislature has a hand in staffing the courts. Courts interpret statutes, so the judiciary shapes what the legislature’s words accomplish.
Where one branch’s authority ends and another’s begins is a recurring question rather than a settled line. In Youngstown Sheet & Tube Co. v. Sawyer (1952), the Supreme Court held that the President lacked authority to seize the country’s steel mills. A concurring opinion in that case supplied a framework still used to think about the problem: presidential power stands at its strongest when the President acts with authorization from Congress, is uncertain when Congress has said nothing, and is at its weakest when the President acts against the expressed or implied will of Congress.
Modern government adds a further wrinkle. Congress writes statutes directing agencies inside the executive branch to fill in details, and how far that direction may go is argued about continuously, with serious people on more than one side. Our page on methods of interpretation sets out those disagreements without taking a position on them.
Reading It for Yourself
The structural provisions are shorter than their reputation suggests. Article I, Sections 7 through 9, Article II, Sections 2 through 4, and Article III, Sections 1 and 2 contain nearly every check named above and can be read in a single sitting of about twenty minutes. If you would rather take them in smaller portions, our reading plan breaks the whole document into twenty-one short sittings, and unfamiliar terms are defined in the glossary.