What are the 3 branches of the U.S. government?

The framework for how the U.S. government works is laid out in less than 4,000 words in Articles I, II, and III of the U.S. Constitution. It would take you less than 15 minutes to read the document that, infused with the thinking of James Madison, was created over the course of less than four months in Philadelphia in the summer of 1787.

What the Founders wrote still governs a U.S. government that as of 2026 employs more than four million civilian and military workers with an annual budget of some $7 trillion. But how does it all work?

The federal government, explained

What each branch is in charge of

Today it is common to think of the three branches of government as being what is called “coequal,” or having roughly the same amount of power. But that was not how the Founding Fathers envisioned it. Consider that Article I lays out the legislative branch and is the longest of the three articles. The framers broadly considered that the executive and judicial branches would play subsidiary roles to the legislature. That has changed over time. Here is a quick overview of the responsibilities of each branch of government.

Legislative (maker of the law): Made up of the Senate, which includes two representatives from every state, and the House of Representatives, where representation is based on state population, the U.S. Congress is a 535-member body responsible for making laws, imposing taxes and allocating money (called the “power of the purse”), declaring war, and investigating government corruption. Congress also has the right to impeach the president, with the House drawing up articles of impeachment and the Senate holding the trial on those articles.

Executive (enforcer of the law): The executive branch includes the president, the vice president, and the president’s cabinet (which includes 15 agencies responsible for topics as wide-ranging as food safety, national defense, and managing that enormous government budget). The president gets to hire, or appoint, the people who run these agencies; the Senate has to approve them. The president also serves as commander-in-chief of U.S. armed forces, but, according to Article I, it is the role of Congress to declare war. (Congressional approval of appointees and declarations of war are examples of “checks and balances,” more on that below.) Other presidential powers include the negotiation of treaties and the granting of pardons.

Judicial (interpreter of the law): The courts are given the responsibility of interpreting laws set out in the Constitution. While state and federal courts rule on most issues, ultimately the Supreme Court has the final say on what is constitutional. As Alexander Hamilton wrote in Federalist Paper 78: “The complete independence of the courts of justice is peculiarly essential in a limited Constitution.” But exactly how that would work remained up in the air until Supreme Court Chief Justice John Marshall created the doctrine of judicial review in the 1803 case of Marbury v. Madison, a case in which the high court for the first time declared an act of Congress unconstitutional while also delivering a dressing-down to Pres. Thomas Jefferson for abuse of power. (In fairness, Pres. John Adams’ appointment of Marbury was an attempt at court-packing, also an abuse of power.) In the landmark ruling Marshall carved out an essential and independent role for the judicial branch that, while not technically outlined in the Constitution, has become settled precedent.

Explore Britannica Premium!

The trusted destination for professionals, college students, and lifelong learners.

SUBSCRIBE

The brilliance of “checks and balances”

Madison was seen as the architect of the Constitution; he and his fellow framers were also good judges of human nature, which is where the system of checks and balances laid out in Federalist Paper 51, entitled “The Structure of the Government Must Furnish the Proper Checks and Balances Between the Different Departments,” comes from.

The idea of checks and balances was not an innovation of the framers—rather, it dates to ancient Greece. French philosopher Montesquieu’s 1748 theory of the separation of powers was also seen as a key inspiration to Madison.

Examples of the ways in which checks and balances work among the branches of the U.S. government include:

• Presidential veto: The president can reject legislation passed by Congress by vetoing it as a check on the power of the legislature. But in a competing check on executive power, a vote by two-thirds of Congress can override the veto.
• Impeachment: As a way to limit illegal or authoritarian actions by the executive, Congress can impeach and remove a president from office. (This has never actually happened, although three presidents have been impeached—but not removed from office—and one has resigned.)
• Presidential appointments: The executive gets to choose his cabinet as well as nominate justices to the Supreme Court, but the Senate has the Article II power of “advice and consent,” meaning it must sign off on those selections.
• Declaring laws unconstitutional: While Congress has the power to write laws, the Supreme Court can declare them unconstitutional and therefore invalid. As a check on that judicial branch power, Congress has the power to seek constitutional amendments, which must be ratified by the states.
• Presidential executive orders: The president can issue orders which carry the force of law but which can be determined to be illegal by the judiciary.
• Declaring war: While the president is the commander-in-chief of the armed forces, the power to declare war rests with Congress.

The implementation of these checks and balances can be seen as tactical and their uses have evolved over time in ways the Founders might not have envisioned. Still, Madison’s argument for them recognized the ways in which the people running each branch of government would try to maneuver for supremacy and the impact that would have on the people being governed. Checks and balances would help create, in Madison’s words,

a government which will protect all parties, the weaker as well as the more powerful.