The Constitution of the United States is the basis for the machinery and institutions of the U.S. government. The Constitution is the world’s oldest charter of national government in continuous use. It was written in 1787 during the Constitutional Convention, which had been convened in the midst of the political crisis that followed the American Revolution. At that time relations were tense between the states and the acting central government, the Continental Congress. The Constitution was an effort to ease those tensions and to create a single political entity from the 13 independent former colonies—the ideal expressed in the motto of the United States, E Pluribus Unum (From Many, One). In 1788, after nine states ratified it, the Constitution became the law of the land. With 27 amendments—or additions—it has remained so.

Articles I, II, and III

To implement these abstract ideas, the Founders established three branches of government—the executive, the legislative, and the judicial. The functions of these branches are described in the first three articles of the Constitution.

Article I is the longest article in the Constitution; it establishes the national legislature called Congress. The Founders divided Congress into a Senate and a House of Representatives because they were afraid of placing too much authority in any one institution. Among other powers, Congress collects taxes, provides for the common defense (meaning that the federal government, not just the states, provides resources for the protection and security of the United States), regulates commerce, raises armies, and declares war. In addition, Article I contains the “necessary and proper clause,” which authorizes Congress to pass any law that it thinks is necessary to carry out its constitutional duties. This provision is very important because it allows Congress to react to situations that may not have existed when the Constitution was written.

Article II establishes an executive department headed by a president and vice president. The article further describes the powers of the offices, the manner of election, and the qualifications for office. Of special significance is the president’s constitutional role as commander of the nation’s armed forces, which assures civilian control over the military. Because the president is the head of the armed forces and only Congress can declare war, the authority of the military is diffused and its power to make decisions is restrained. The Constitution also grants the president the authority to make treaties with other nations. However, to limit abuse of this power, the Constitution requires treaties to be ratified by two-thirds of the Senate.

Article III directs that the federal judicial power be placed in a Supreme Court and in other courts as directed by Congress. This brief article also lists the kinds of cases that fall specifically under the jurisdiction of the federal courts.

Articles IV, V, VI, and VII

Along with the preamble, the first three articles are the most familiar parts of the Constitution. There are, however, four additional articles. Article IV sets up cooperative arrangements between the states and the federal government regarding fugitives and criminals, and requires that states respect one other and one other’s citizens. It also establishes the process by which territories become states, an important function during the 19th and early 20th centuries. Finally, Article IV guarantees a republican—or representative—form of government for all states.

Article V establishes procedures for amending the Constitution. The Founders developed a method for changing the Constitution so that it could be adapted to changing times. To maintain a balance between the power of the federal government and that of the state governments, the amendment process requires approval by majorities of legislative bodies at both the state and federal levels. Only a two-thirds majority of both houses of Congress can propose a constitutional revision; the legislatures of three-quarters of the states must then ratify the amendment for it to take effect. The Constitution also provides another amendment method, though it has never been used: The legislatures of two-thirds of the states can call a constitutional convention to propose amendments to the Constitution. Any proposal agreed upon must then be ratified by three-quarters of the states.

Article VI is a catchall article; its most important section establishes the Constitution and the laws of the United States as “the supreme Law of the Land.” Article VII of the Constitution establishes procedures that were used in 1788 and 1789 for the approval and subsequent adoption of the document by the states.


No sooner was the Constitution accepted than both individuals and states insisted on additions to protect the people from possible abuses by the new federal government. In 1790 Congress and the states ratified ten amendments known as the Bill of Rights. These amendments guarantee personal liberties and prevent the federal government from infringing on the rights of states and citizens.

For example, the First Amendment—the most far-reaching amendment in the Bill of Rights—prohibits Congress from establishing an official state religion and from preventing Americans from the free exercise of their religion. It also prohibits the government from interfering with freedom of speech, freedom of the press, and the right “peaceably to assemble.” Other amendments in the Bill of Rights confer on the people the right to speedy trials, to be secure in their homes, and to own and carry arms. The Fifth Amendment states that people cannot be deprived of life, liberty, or property “without due process of law”—that is, without a fair trial.

Besides the Bill of Rights, there have been only 17 other amendments to the Constitution in the more than 200 years of its existence. Of these, some of the most important are the 15th, 19th, and 26th amendments, which, respectively, gave blacks, women, and 18-year-olds the right to vote. Also important are the 17th Amendment, which gave the people the right to elect United States senators, and the 22nd Amendment, which restricted the number of terms a president can serve to two. These amendments extended the principles of democracy to more Americans, and in the case of the president, limited the power of a chief executive by restricting the length of his or her tenure. Besides these amendments, the 14th Amendment is an important safeguard for minority rights because under its “due process” clause, it extends the protections of the Bill of Rights to individual residents of states. In the same way that the Bill of Rights limits federal power, the 14th Amendment limits the power of the states over their citizens.

Importance of the Constitution

The Constitution of the United States embodies the principle that out of many different peoples, one national society can be created. The Founders wanted unity and stability. But they also wanted to safeguard the rights and liberties of states and individuals by balancing power among individuals, states, and the national government. The result is a system of shared functions designed to prevent any one element from gaining too much power.