He was a member of the United States House of Representatives for 38 years. He represented central Illinois' 18th congressional district, and was the GOP leader in Congress during the Ronald Reagan, George H. W. Bush and Bill Clinton presidencies from 1981 through 1995. He as Minority Leader from 1981 through 1995. He was also Minority Whip for 6 years from 1975 through 1981.