The authority of Congress to investigate is an implied constitutional power, one that Congress has exercised since the earliest days of the republic. Although not expressly authorized in the Constitution, the Supreme Court has firmly established Congress's investigative authority as an essential part of its legislative responsibilities. James Madison anticipated the significance of congressional inquiry in The Federalist, No. 51 when he urged: "In framing a government which is to be administered by men over men . . . you must first enable the government to control the governed; and in the next place oblige it to control itself." Today, congressional oversight enables House and Senate members to serve as the eyes and ears of the American public.