 Upon his return to the Senate in 1957, Cooper was assigned to the Senate Foreign Relations Committee. In 1959, he challenged Illinois Senator Everett Dirksen to become the Republican floor leader in the Senate, but lost by four votes. In a 1960 poll of fifty journalists conducted by Newsweek magazine, Cooper was named the ablest Republican member of the Senate. He helped author and co-sponsored the National Defense Education Act. Together with Senator Jennings Randolph, he sponsored the Appalachian Regional Development Act, designed to address the prevalent poverty in Appalachia. He succeeded in gaining more state and local control over the anti-poverty group Volunteers in Service to America. He was a vigorous opponent of measures designed to weaken the Tennessee Valley Authority.
