<P> Congress has authority over financial and budgetary policy through the enumerated power to "lay and collect Taxes, Duties, Imposts and Excises, to pay the Debts and provide for the common Defence and general Welfare of the United States". There is vast authority over budgets, although analyst Eric Patashnik suggested that much of Congress's power to manage the budget has been lost when the welfare state expanded since "entitlements were institutionally detached from Congress's ordinary legislative routine and rhythm". Another factor leading to less control over the budget was a Keynesian belief that balanced budgets were unnecessary . </P> <P> The Sixteenth Amendment in 1913 extended congressional power of taxation to include income taxes without apportionment among the several States, and without regard to any census or enumeration . The Constitution also grants Congress the exclusive power to appropriate funds, and this power of the purse is one of Congress's primary checks on the executive branch . Congress can borrow money on the credit of the United States, regulate commerce with foreign nations and among the states, and coin money . Generally, both the Senate and the House of Representatives have equal legislative authority, although only the House may originate revenue and appropriation bills . </P> <P> Congress has an important role in national defense, including the exclusive power to declare war, to raise and maintain the armed forces, and to make rules for the military . Some critics charge that the executive branch has usurped Congress's constitutionally defined task of declaring war . While historically presidents initiated the process for going to war, they asked for and received formal war declarations from Congress for the War of 1812, the Mexican--American War, the Spanish--American War, World War I, and World War II, although President Theodore Roosevelt's military move into Panama in 1903 did not get congressional approval . In the early days after the North Korean invasion of 1950, President Truman described the American response as a "police action". According to Time magazine in 1970, "U.S. presidents (had) ordered troops into position or action without a formal congressional declaration a total of 149 times ." In 1993, Michael Kinsley wrote that "Congress's war power has become the most flagrantly disregarded provision in the Constitution," and that the "real erosion (of Congress's war power) began after World War II ." Disagreement about the extent of congressional versus presidential power regarding war has been present periodically throughout the nation's history ." </P> <P> Congress can establish post offices and post roads, issue patents and copyrights, fix standards of weights and measures, establish Courts inferior to the Supreme Court, and "make all Laws which shall be necessary and proper for carrying into Execution the foregoing Powers, and all other Powers vested by this Constitution in the Government of the United States, or in any Department or Officer thereof ." Article Four gives Congress the power to admit new states into the Union . </P>

Why is there a senate and a house of representatives