The legislative branch of the US federal government. Provided for in Article I of the US Constitution, Congress is divided into two constituent houses: the lower, the House of Representatives, in which membership is based on the population of each state; and the upper, the Senate, in which each state has two members. Representatives serve a two-year term and Senators a six-year term. Congressional powers include the collection of taxes and duties, the provision for common defence, general welfare, the regulation of commerce, patents and copyrights, the declaration of war, raising of armies, and maintenance of a navy, and the establishment of the post offices and federal courts. Originally, Congress was expected to hold the initiative in the federal government, but the emergence of the President as a national party leader has resulted in the continuous fluctuation in the balance of power between legislature and executive. Much of the effective work of Congress is now done in powerful standing committees dealing with major areas of policy.