How the U.S. government works

Last reviewed: June 3, 2026

The U.S. federal government is built on three independent branches that share, watch over, and limit each other. The framers of the 1787 Constitution were wary of concentrated power; the system they designed deliberately makes it slow to act unilaterally, and that is by design.

1. The three branches

Executive branch — the President

The President leads the executive branch and is both head of state and head of government. The role combines duties that are split between two figures in many parliamentary democracies. The President:

• Enforces federal laws and runs the federal administration (cabinet, agencies, embassies, military).
• Is commander-in-chief of the armed forces.
• Signs or vetoes bills passed by Congress.
• Nominates federal judges (including Supreme Court justices), ambassadors, cabinet secretaries, and senior agency officials — subject to Senate confirmation.
• Negotiates treaties (which the Senate ratifies).
• Serves a 4-year term and can be re-elected once (22nd Amendment, 1951).

Legislative branch — Congress

Congress is bicameral. Both chambers must agree for a federal law to pass.

• Senate: 100 senators, two per state regardless of population. Six-year terms, with one third up for election every two years. The Senate confirms presidential nominations and ratifies treaties.
• House of Representatives: 435 voting representatives, allocated by state population and re-apportioned every ten years after the census. Two-year terms — meaning the entire House is up for election every other year.
• Together, Congress writes federal statutes, sets the federal budget, and decides on taxes and tariffs.
• Congress can override a presidential veto with a two-thirds vote in each chamber.
• Congress can impeach the President, the Vice President, judges, and other federal officers (House charges; Senate tries).

Judicial branch — the courts

At the top sits the Supreme Court: nine justices nominated by the President and confirmed by the Senate, serving for life or until they retire or resign. Below it sit 13 federal Courts of Appeals (the "circuits") and 94 federal District Courts. The federal judiciary:

• Decides federal-law and constitutional cases.
• Can declare a law — federal or state — unconstitutional (judicial review, established in Marbury v. Madison, 1803).
• Resolves disputes between states, and certain disputes involving foreign parties.

Life tenure is the most striking feature for European observers: it gives Supreme Court appointments unusual political weight, since a single justice can shape constitutional doctrine for decades.

2. How a bill becomes law, step by step

A federal law never depends on one person. A proposal (a "bill") must clear a full path before it becomes a "law":

1. Introduction: a member of the House or Senate introduces the bill. Revenue (tax) bills must start in the House of Representatives.
2. Committee: the bill goes to a specialized committee, which studies, amends, holds hearings — or quietly lets it die without a vote (the most common outcome).
3. Debate and vote in the first chamber: if it clears committee, the bill is debated and voted on by the full chamber.
4. The second chamber: the other chamber repeats the process and may pass a different version.
5. Reconciling the versions: if the two versions differ, a conference committee negotiates a single text, which both chambers must re-pass identically.
6. The President: the identical text goes to the President, who can sign it (it becomes law), veto it, or do nothing (it becomes law after 10 days, unless Congress has adjourned — the "pocket veto").
7. Overriding a veto: Congress can override a veto with a two-thirds vote in each chamber — a high bar that is rarely met.

This path explains why so many bills fail: a block at any single step is enough. For the calendar that renews these chambers, see U.S. elections explained.

3. How the Senate really works: the filibuster

One Senate quirk changes everything: the filibuster. To end debate on most bills and move to a final vote, 60 of 100 senators must agree (a "cloture" vote). In practice, a minority of 41 senators can block a bill even when a simple majority supports it.

• A simple majority (51) can pass a bill, but cannot end the debate that precedes it.
• Some procedures bypass the filibuster: budget reconciliation (tax and spending bills) and confirmation of nominations, including judges, now need only 51 votes.
• The filibuster does not exist in the House of Representatives, where a simple majority is enough.

This is one reason the Senate, not the House, is often where major reforms slow down or die.

4. Judicial review, in plain terms (Marbury v. Madison)

The Constitution does not explicitly say the Supreme Court can strike down a law. That power — judicial review — was established by the Court itself in 1803 in Marbury v. Madison.

In plain terms: the Court had to settle a dispute but found that the very law meant to give it the power to act conflicted with the Constitution. Rather than apply that law, the Court held that a law in conflict with the Constitution is void, and that it falls to the courts to say so. Since then, this principle lets the federal judiciary invalidate laws — federal or state — that it finds unconstitutional. The Court acts only when a real case reaches it; it issues no advisory opinions on laws in the abstract.

5. Checks and balances in practice

Each branch has tools to limit the others. Examples:

• The President can veto laws — Congress can override with two thirds of each chamber.
• The President nominates federal judges — the Senate confirms or rejects.
• The Supreme Court can strike down a law — but only when a real case reaches it; the Court does not issue advisory opinions.
• Congress can impeach and remove federal officials — the bar is high (two-thirds Senate conviction).
• Congress decides how to spend federal money — but the President signs the budget and can veto it.

The result is a slow, friction-heavy system. Important reforms typically need either rare bipartisan majorities, or the alignment of all three branches under one party's control.

6. Federalism: a second balance, vertical this time

On top of the horizontal split among branches, there is a vertical split between Washington and the 50 states. Approximate distribution:

• Federal: defense, foreign policy, currency, immigration, interstate commerce, customs, federal taxation, social security, federal antitrust.
• States: education, criminal law, family law, most healthcare regulation, state taxation, state-level voting rules, professional licensing.
• Concurrent (both): taxation, courts, roads, environmental regulation, public-health emergencies.

For more detail, see States vs federal government.

Concrete examples of this split:

• Cannabis: still illegal federally, yet many states have legalized it for medical or recreational use — the most visible clash between federal and state law.
• Driving: speed limits, licensing, and the driving age are set entirely by each state.
• Death penalty: some states apply it, others have abolished it; criminal law is mostly a state matter.
• Taxes: there is a federal income tax, but also state taxes that vary widely — a few states levy no income tax at all.
• Immigration and currency: exclusively federal — a state cannot set its own immigration policy or issue its own money.

7. Term lengths and the election cycle

Federal elections fall every two years, on the Tuesday after the first Monday in November. Even years without a presidential race (2026, 2030…) are "midterm" elections, renewing the entire House and one third of the Senate. The number of House seats per state is recalculated every ten years after the census.

8. The Constitution

• Written in 1787, ratified in 1788, in force since 1789. The oldest written national constitution still in use.
• Supreme law of the land — every other law must be consistent with it.
• 27 amendments. The first ten (the Bill of Rights, 1791) protect free speech, religion, press, assembly, the right to bear arms, due process, and more.
• Hard to amend: two thirds of each chamber of Congress, then ratification by three quarters of the states.

9. The administrative state: the cabinet and executive departments

Day-to-day federal action runs through the executive branch under the President. At its top, the cabinet brings together the secretaries — the U.S. equivalent of ministers — who head the main executive departments. They are nominated by the President and confirmed by the Senate.

• Department of State: diplomacy and foreign affairs.
• Department of the Treasury: public finances, debt, and taxation (the IRS sits under it).
• Department of Defense: the armed forces (at the Pentagon).
• Department of Justice: led by the Attorney General, in charge of federal prosecutions (the FBI sits under it).
• Department of Homeland Security: domestic security and immigration (USCIS sits under it).

Alongside the departments sit many federal agencies — the EPA (environment), the FDA (food and drugs), the FCC (communications), and more. They issue regulations within the authority Congress has delegated to them, and federal courts can review their actions for legality and constitutionality.

10. Common European misreadings

• "The President can do X." Often no — many decisions need Congress, the Senate, or both. Executive orders are bounded by statute and the Constitution.
• "The Supreme Court is political." Justices have legal philosophies, but they react to cases, not policy agendas; not every controversial issue lands at the Court.
• "Washington decides for the country." Most rules touching daily life — schools, marriage, criminal sentencing, road rules — are written in state capitals.

Related articles:

• U.S. elections explained
• States vs federal
• What is the United States?
• USA vs Europe