The United States Congress is the legislature of the federal government of the United States. It is bicameral, being composed of a lower body, the House of Representatives, and an upper body, the Senate. The Congress meets in the United States Capitol in Washington, D.C. Both senators and representatives are chosen through direct election, though vacancies in the Senate may be filled by a governor's appointment. Congress has 535 voting members: 100 senators and 435 representatives. The vice president of the United States has a vote in the Senate only when senators are evenly divided. The House of Representatives has six non-voting members.The sitting of a Congress is for a two-year term, at present, beginning every other January. Elections are held every even-numbered year on Election Day. The members of the House of Representatives are elected for the two-year term of a Congress. The Reapportionment Act of 1929 establishes that there be 435 Representatives and the Uniform Congressional Redisistricting Act requires that they be elected from single-member constituencies or districts. It is also required that the Congressional districts be apportioned among states by population every ten years using the United States Census results, provided that each state has at least one Congressional representative. Each senator is elected at-large in their state for a six-year term, with terms staggered, so every two years approximately one-third of the Senate is up for election. Each state, regardless of population or size, has two senators, so currently, there are 100 senators for the 50 states.

Article One of the United States Constitution requires that members of Congress must be at least 25 years old (House) or at least 30 years old (Senate), have been a citizen of the United States for seven (House) or nine (Senate) years, and be an inhabitant of the state which they represent. Members in both chambers may stand for re-election an unlimited number of times.

The Congress was created by the Constitution of the United States and first met in 1789, replacing in its legislative function the Congress of the Confederation. Although not legally mandated, in practice since the 19th century, Congress members are typically affiliated with one of the two major parties, the Democratic Party or the Republican Party, and only rarely with a third party or independents affiliated with no party. In the case of the latter, the lack of affiliation with a political party does not mean that such members are unable to caucus with members of the political parties. Members can also switch parties at any time, although this is quite uncommon.

The Federal Bureau of Investigation (FBI) is the domestic intelligence and security service of the United States and its principal federal law enforcement agency. Operating under the jurisdiction of the United States Department of Justice, the FBI is also a member of the U.S. Intelligence Community and reports to both the Attorney General and the Director of National Intelligence. A leading U.S. counter-terrorism, counterintelligence, and criminal investigative organization, the FBI has jurisdiction over violations of more than 200 categories of federal crimes.Although many of the FBI's functions are unique, its activities in support of national security are comparable to those of the British MI5, the New Zealand GCSB and the Russian FSB. Unlike the Central Intelligence Agency (CIA), which has no law enforcement authority and is focused on intelligence collection abroad, the FBI is primarily a domestic agency, maintaining 56 field offices in major cities throughout the United States, and more than 400 resident agencies in smaller cities and areas across the nation. At an FBI field office, a senior-level FBI officer concurrently serves as the representative of the Director of National Intelligence.Despite its domestic focus, the FBI also maintains a significant international footprint, operating 60 Legal Attache (LEGAT) offices and 15 sub-offices in U.S. embassies and consulates across the globe. These foreign offices exist primarily for the purpose of coordination with foreign security services and do not usually conduct unilateral operations in the host countries. The FBI can and does at times carry out secret activities overseas, just as the CIA has a limited domestic function; these activities generally require coordination across government agencies.

The FBI was established in 1908 as the Bureau of Investigation, the BOI or BI for short. Its name was changed to the Federal Bureau of Investigation (FBI) in 1935. The FBI headquarters is the J. Edgar Hoover Building, located in Washington, D.C.