If the president is unable to perform his duties, the vice-president takes over.
If the president is unable to perform his duties, the vice-president takes over.

The chain of command of the United States government should really be called the chains of command. As students are taught from elementary school on, the U.S. government is broken into three branches: executive (the White House and cabinet departments), legislative (Congress) and judicial (the courts). No one branch is subservient to any other. Rather, all three work in tandem to enact, enforce and review laws and policies. Each branch has its own distinct structure and chain of command.

The White House

The executive branch of the U.S. government is led by the president, whose main role is to administer the government, enforce laws, conduct foreign relations and command the military. This puts the president in charge of an executive branch that employs more than four million people. While the vice-president is nominally the second-ranking individual in the executive branch, he technically has no official responsibilities other than to preside over the Senate. The vice-president, however, assumes the office's responsibilities if the president is incapacitated. Cabinet secretaries, for example, the secretary of state, report directly to the president. The president's chief of staff is in charge of White House staff while the heads of other components of the Executive Office of the President -- for example, the director of the Office of Management and Budget -- report directly to the president.

The president is also commander-in-chief of the armed forces. The military chain of command runs from the president to the secretary of defense and then to the commanders of the unified combatant commands, for example, the general or admiral in charge of USCENTCOM, U.S. Central Command, which oversees U.S. forces in the Middle East and Southwest Asia. The Chairman of the Joint Chiefs of Staff, the highest-ranking officer in the armed forces, acts as the president's chief military advisor but has no official place in the chain of command.

The House of Representatives

The legislative branch is broken into two bodies: the House and the Senate. The house, consisting of 435 elected members, is led by the speaker of the House, whose job is to preside over the elected body. Below the speaker are the majority leader, elected by members from the party with a majority of members, and the minority leader, elected by representatives of the other party. Finally, party whips help their respective leaders in pushing their party's legislative agenda through the House.

The Senate

The Senate is structured similarly to the House, but with a few key differences. First of all, there is no speaker in the Senate. While the vice-president officially presides over the Senate, in reality, it is the majority leader who sets the legislative agenda each day. As in the House, party whips assist the majority and minority leaders in their day-to-day duties, and take over in their absence. Finally, each party has a conference chairperson to preside over private party meetings.

The Courts

The judiciary does not make or enforce law, but interprets it, applies it to specific cases and determines constitutional questions. The highest court is the U.S. Supreme Court, led by the chief justice. The decisions of the Supreme Court supersede those of lower courts. These lower courts are made up of federal courts, whose decisions are often reviewed by federal appeals courts. The chief justice does not oversee the other workings of the judicial system, for example, federal prosecutors or prisons, which are within the purview of the attorney general.