The federal government of the United States (U.S. federal government or U.S. government) is the national government of the United States.
The United States federal government is composed of three distinct branches: legislative, executive, and judicial. The powers of these three branches are defined and vested by the Constitution of the United States, which has been in effect since 1789. The powers and duties of these branches are further defined by acts of Congress, including the creation of executive departments and courts subordinate to the Supreme Court of the United States.
In the federal division of power, the federal government shares sovereignty with each of the 50 states in their respective territories. United States law recognizes Indigenous tribes as possessing sovereign powers, while being subject to federal jurisdiction.
The full name of the republic is the "United States of America". No other names appear in the Constitution, (except for the shorter “United States” for which it is usually addressed in it) and this is the name that appears on currency, in treaties and documents, and in legal cases to which the nation is a party. The terms "Government of the United States of America" or "United States Government" are often used in official documents to represent the federal government as distinct from the states collectively.
In casual conversation or writing, the term "Federal Government" is often used, and the term "U.S. Government" is sometimes used. The terms "Federal" and "National" in government agency or program names generally indicate affiliation with the federal government; for instance, the Federal Bureau of Investigation, National Oceanic and Atmospheric Administration, and National Park Service. "Washington" and "White House" are sometimes used as a metonym for the federal government because Washington, D.C., is the seat of government and the latter as its headquarters, respectively.
The U.S. government was established in a series of initiatives in the late 18th century, starting with its decision to establish the Continental Army and appoint George Washington as its commander. The Continental Army resisted the British during the American Revolutionary War, which began in 1775. The following year, in July 1776, delegates to the Second Continental Congress, gathered at present-day Independence Hall in the colonial capital of Philadelphia, unanimously adopted the United States Declaration of Independence with each of the 56 colonial-era delegates signing it. In September 1783, the Thirteen Colonies ultimately prevailed over the British in the Revolutionary War, establishing the United States as an independent nation. On March 4, 1789, again gathered in Philadelphia, the colonies ratified and adopted the Constitution of the United States, which established the nation's federal rule of law and was largely based on federalism, republicanism and democracy.
Under the U.S. Constitution, the power of the U.S. federal government is shared between its executive, legislative, and judicial branches, state governments, and the people. It is a mixed system, neither pure republic nor pure democracy, and often described as a democratic republic, representative democracy, or constitutional republic.
The interpretation and execution of these principles, including what powers the federal government should have and how those powers can be exercised, have been debated ever since the adoption of the Constitution. Some make a case for expansive federal powers while others argue for a more limited role for the central government in relation to individuals, the states, or other recognized entities.
Since the American Civil War, the powers of the federal government have expanded greatly, although there have been periods since that time when the legislative branch was more powerful, including the decades immediately following the Civil War, or when states' rights proponents have succeeded in limiting federal power through legislative action, executive prerogative or by a constitutional interpretation by the courts.
One of the theoretical pillars of the U.S. Constitution is the idea of "checks and balances" among the powers and responsibilities of the three branches of American government: the executive, the legislative, and the judiciary. For example, while Congress, the federal government's legislative branch, has the power to create laws, the executive branch under the president can veto legislation, an act which, in turn, can be overridden by Congress. The president nominates judges to the nation's highest judiciary authority, the Supreme Court (as well as to lower federal courts), but those nominees must be approved by Congress. The Supreme Court, in turn, can invalidate unconstitutional laws passed by the Congress.
The United States Congress, under Article I of the Constitution, is the legislative branch of the federal government. It is bicameral, comprising the House of Representatives and the Senate.
The U.S. House of Representatives is made up of 435 voting members, each of whom represents a congressional district in a state from where they were elected. Apportionment of seats among the 50 states is determined by state populations, and it is updated after each decennial U.S. Census. Each member serves a two-year term.
In order to be elected as a representative, an individual must be at least 25 years of age, must have been a U.S. citizen for at least seven years, and must live in the state that they represent.
In addition to the 435 voting members, there are six non-voting members, consisting of five delegates and one resident commissioner. There is one delegate each from Washington, D.C., Guam, the Virgin Islands, American Samoa, the Commonwealth of the Northern Mariana Islands, and a resident commissioner from Puerto Rico.
Unlike the U.S. Senate, all members of the U.S. House must be elected and cannot be appointed. In the case of a vacancy, the seat must be filled through a special election, as required under Article 1 of the U.S. Constitution.
In contrast, the Senate is made up of two senators from each state, regardless of population. There are currently 100 senators (2 from each of the 50 states), who each serve six-year terms. Approximately one-third of the Senate stands for election every two years.
If a vacancy occurs, the state governor appoints a replacement to complete the term or to hold the office until a special election can take place.
The House and Senate each have particular exclusive powers. For example, the Senate must approve (give "advice and consent" to) many important presidential appointments, including cabinet officers, federal judges (including nominees to the Supreme Court), department secretaries (heads of federal executive branch departments), U.S. military and naval officers, and ambassadors to foreign countries. All legislative bills for raising revenue must originate in the House of Representatives. The approval of both chambers is required to pass all legislation, which then may only become law by being signed by the president (or, if the president vetoes the bill, both houses of Congress then re-pass the bill, but by a two-thirds majority of each chamber, in which case the bill becomes law without the president's signature). The powers of Congress are limited to those enumerated in the Constitution; all other powers are reserved to the states and the people.