Article One of the United States Constitution describes the powers of the legislative branch of the United States government, known as Congress, which includes the House of Representatives and the Senate. The Article establishes the manner of election and qualifications of members of each House. In addition, it outlines legislative procedure and enumerates the powers vested in the legislative branch. Finally, it establishes limits on federal and state legislative powers.
Each of the first three Articles of the Constitution concern one of the three branches of the federal government. The legislative branch is established under Article One, the executive branch under Article Two, and the judicial branch under Article Three.
Amendments to Article One, unlike amendments to other articles, are explicitly restricted by the Constitution (these restrictions are imposed by Article Five). For example, no amendment made prior to 1808 could affect the first and fourth clauses of Section Nine. The first clause prevented Congress from prohibiting the slave trade until 1808; the fourth barred any direct taxes that were not apportioned among the States according to population.
