The U.S. Constitution established three branches of government: executive, judicial and legislative. Article I of the Constitution defines the legislative branch and vests power to legislate in the U.S. Congress. Article II defines the executive powers of the President and Article III creates the federal courts. This system of government is called the "separation of powers" and allows each branch to operate independently. However, the drafters of the Constitution created a series of “checks and balances” to prevent the concentration of power in any one branch and to protect the rights and liberties of citizens. For example,
The President can veto bills approved by Congress. The President nominates individuals to serve in the Federal judiciary who must be confirmed by the Senate.
The Supreme Court can declare a law enacted by Congress or an action by the President unconstitutional.
Congress can impeach the President and Federal court justices and judges. Congress can also override a presidential veto of legislation with a two-thirds majority vote by Members present in both the House and the Senate, provided there is a quorum.
Below is a very brief overview of the powers of each federal branch of government.
The power of the executive branch is vested in the President who also serves as Commander in Chief of the Armed Forces. The President appoints the Cabinet, subject to confirmation by the Senate, and oversees the various federal agencies and departments. To serve as President, an individual must be a natural-born citizen of the U.S.; be at least 35 years of age; and have resided in the country for at least 14 years. Once elected, the President serves a term of four years and may be re-elected only once.
The tradition of the Cabinet dates back to the beginnings of the Presidency. A key role for Cabinet members is to advise the President on any subject relating to the duties of their respective offices. The Cabinet includes the Vice President and the heads of 15 executive departments: the Secretaries of Agriculture, Commerce, Defense, Education, Energy, Health and Human Services, Homeland Security, Housing and Urban Development, Interior, Labor, State, Transportation, Treasury and Veterans Affairs, and the Attorney General.
Under President George W. Bush, four other positions received Cabinet-level rank: Administrator, Environmental Protection Agency; Director, Office of Management and Budget; Director, National Drug Control Policy; and U.S. Trade Representative.
Federal courts often are called the “guardians of the Constitution” because their rulings protect rights and liberties guaranteed by it. Through fair and impartial judgments, the federal courts interpret and apply the law to resolve disputes. Courts do not make the laws, a role reserved for Congress, nor do they have the power to enforce laws, a role reserved for the President and the executive branch departments and agencies.
The authors of the Constitution believed that an independent federal judiciary was essential to ensure fairness and equal justice for all citizens. They drafted the Constitution to promote judicial independence in two major ways:
Federal judges are appointed for life and they can only be removed from office through impeachment and conviction by Congress for "treason, bribery, or other high crimes and misdemeanors."
Neither the President nor Congress can reduce the compensation of federal judges while they serve on the bench.
These two protections were designed to create an independent judiciary that can decide cases free from political influence. Article III of the Constitution created the following federal courts: the U.S. Supreme Court; U.S. Courts of Appeals; U.S. District Courts and Bankruptcy Courts.
The Constitution grants Congress "all legislative powers" in the national government. Article I, Section 8, of the Constitution lists a wide range of congressional powers, including: coining money; maintaining a military; declaring war on other countries; and regulating interstate and foreign commerce. Congress also controls federal taxing and spending policies—one of the most important sources of power in the government. The Constitution also gives Congress the authority to "make all laws which shall be necessary and proper," an implied source of power sometimes called the “Elastic Clause.”
One of the most important implied powers is its authority to investigate and oversee the executive branch and its agencies. Through this responsibility - known as oversight - Congress can summon senior officials to answer questions, order audits of agencies and convene hearings on matters of general public concern. Sometimes hearings are held to identify problems that can be addressed through new laws and other hearings are held to raise public awareness about an issue.
Congress also shares powers with the president in certain matters such as framing U.S. foreign policy and control over the military. For example, while the president negotiates treaties, the Senate must ratify them. Also, while Congress can declare war and approve funds for the military, the president is the commander-in-chief.
Laws passed by Congress are sometimes called "statutory law." This term includes the acts passed by Congress as well as documents associated with the legislative process such as proposed bills, committee reports and the record of hearings.
Congress is a bicameral institution, consisting of both the Senate (upper house) and the House of Representatives (lower house). Members of Congress are elected by a direct vote of the people of the state they represent. More information about each chamber appears below.
Agencies that provide support services for Congress are also part of the legislative branch, including: Government Printing Office; Library of Congress; Congressional Budget Office; Government Accountability Office; and the Architect of the Capitol.
House of Representatives
The House has 435 members (plus five non-voting delegates described below) with each representing an area of a state, known as a congressional district. The number of representatives is based on the number of districts with each state guaranteed one seat. Congressional districts are redrawn every ten years after each census.
All Members and Delegates are elected every two years (with the exception of Puerto Rico.) They must be 25 years old, a citizen for at least seven years, and a resident of the state from which they are elected. The four non-voting delegates represent Guam, American Samoa, Virgin Islands and the District of Columbia. One Resident Commissioner is elected every four years to represent Puerto Rico.
Two special jobs are reserved for the House including the authority to:
Start laws that make people pay taxes.
Decide if a government official should be put on trial before the Senate if s/he commits a crime against the country.
The Senate has 100 members representing two from each state. The first elected is called the “Senior” Senator while the other is the “Junior” Senator. They serve six year terms and one-third of the Senate is elected every second year. The two Senators from each state are not elected at the same time. They must be 30 years old, a citizen for at least nine years, and a resident of the state from which they are elected.
Under the Constitution, the Vice President has formal control over the Senate and is known as the President of the Senate. However, the vice president is only present for important ceremonies and to cast a tie-breaking vote.
The Senate also has certain special roles including the authority to:
Confirm or disapprove any treaties the President drafts.
Confirm or disapprove Presidential appointments such as the Cabinet, Supreme Court Justices and ambassadors.
Background Information & Resources
For a very extensive glossary of terms, arranged alphabetically, see the C-SPAN web site at
Role of Congress
Overview of the Authorization-Appropriations Process, CRS Report-December 2006
Bills and Resolutions: Examples of How Each Kind Is Used, CRS Report-December 2006
Tying it All Together, U.S. House of Representatives
Federal Budget Process