Overview of the U.S. Constitution

Significantly, the body of the Constitution begins with the legislative branch, indicating the importance the framers placed on the lawmaking power. Article 1 divides Congress into the House of Representatives and the Senate and sets the terms of office for members at two and six years, respectively. House elections are held every two years; Senate seats are divided into three groups, one of which is up for election every two years. To be eligible for election to the House, a person must be 25 years old, be a citizen for seven years, and be a resident of the state. Candidates for the Senate must be 30 years old, be a citizen for nine years, and live in the state. Originally, senators were elected by state legislatures but have been elected by statewide popular vote since ratification of the 17th Amendment in 1913. Article 1 identifies the presiding officers of the two chambers as the Speaker of the House and, for the Senate, the vice president.

Article 1 of the Constitution details the enumerated powers of Congress. An enumerated power is one specifically granted to Congress by Article 1, Section 8, of the U.S. Constitution. Congress also holds implied powers. An implied power is a power assumed by Congress through interpretation of the necessary and proper clause found in paragraph 18 of Article 1, Section 8, of the Constitution. The necessary and proper clause, or elastic clause, gives Congress the power to make laws that are necessary to carry out the powers that are granted by the Constitution. Over the years, Congress has exercised this broad power to legislate in many more areas than would be imaginable under the enumerated powers alone.

A key congressional power is the ability to raise revenue by imposing taxes. Under the Articles of Confederation, only the states had the power to tax. The Confederation Congress could ask the states for money to meet national needs, but it could neither tax the people or the states nor compel the states to supply the requested funds. By giving the new Congress the power to tax, the delegates to the Constitutional Convention made the new national government more viable.

Article 2 of the Constitution outlines the terms of office and the powers of the president of the United States, who heads the executive branch of the U.S. government. The president serves for four years and may be reelected. Under the 22nd Amendment, ratified in 1951, a person may be elected to only two terms as president; anyone who succeeds to the presidency to fill a vacancy and serves more than two years can only be elected to one additional term. To be elected president, a person must be 35 years old, be a natural-born citizen of the United States, and have lived in the United States for 14 years. As noted earlier, the framers established the electoral college to select the president and the vice president. The vice president's only specified duty is to serve as the presiding officer of the Senate.

The president is responsible for enforcing laws. Although Article 2 names the president as commander in chief of the armed forces, Article 2, Section 8, stipulates that only Congress has the power to declare war. Enumerated powers given to the president include negotiating treaties with other countries and nominating federal officials and judges, though both treaties and those nominations are subject to the consent of the Senate.

The judicial branch is made up of the court system. The Constitution created one Supreme Court and gave Congress the power to create other inferior, or lower, courts. The Supreme Court can rule directly on all cases involving a dispute between the states or one involving foreign officials. It can review appeals of decisions made by the lower courts on issues of constitutional or federal law. Through the principle of judicial review, established in the case Marbury v. Madison (1803)—but not specifically granted by the Constitution—the judiciary also holds the power to review a federal law or executive branch action for constitutionality.

The Constitution provides only a sketchy outline of the federal judiciary, as the framers left it up to Congress to fill in the details. The First Congress created a three-level court system with district courts that function as federal trial courts that handle both criminal and civil cases; circuit courts that hear appeals on the decisions of those lower courts; and the U.S. Supreme Court, which has the final word on federal cases. The number of justices on the Supreme Court is not set by the Constitution but established by law. While the number of justices has been set at nine since the 1860s, the first Supreme Court had only six. The Constitution does provide that members of the federal judiciary shall serve for life "during good Behaviour." Under Article 3, Section 4, federal judges, as "civil Officers," are subject to impeachment.