A Bicameral Congress
"GOVERNMENT IMPLIES THE POWER OF MAKING LAWS."
ALEXANDER HAMILTON, The Federalist, 1787-1788
Article I of the Constitution grants all legislative powers of the federal government to a Congress divided into two chambers, a Senate and a House of Representatives. The Senate, the smaller of the two, is composed of two members for each state as provided by the Constitution. Membership in the House is based on population and its size is therefore not specified in the Constitution.
For more than 100 years after the adoption of the Constitution, senators were not elected by direct vote of the people but were chosen by state legislatures. Senators were looked on as representatives of their home states. Their duty was to ensure that their states were treated equally in all legislation. The 17th Amendment, adopted in 1913, provided for direct election of the Senate.
The delegates to the Constitutional Convention reasoned that if two separate groups -- one representing state governments and one representing the people -- must both approve every proposed law, there would be little danger of Congress passing laws hurriedly or carelessly. One house could always check the other in the manner of the British Parliament. Passage of the 17th Amendment did not substantially alter this balance of power between the two houses.
While there was intense debate in the Convention over the makeup and powers of Congress, many delegates believed that the legislative branch would be relatively unimportant. A few believed that the Congress would concern itself largely with external affairs, leaving domestic matters to state and local governments. These views were clearly wide of the mark. The Congress has proved to be exceedingly active, with broad powers and authority in all matters of national concern. While its strength vis-a-vis the executive branch has waxed and waned at different periods of American history, the Congress has never been impotent or a rubber stamp for presidential decisions.