Thomas was a member of numerous committees in the House, among them Irrigation and Reclamations, Pensions, Labor, Elections, Appropriations, the Independent Offices Subcommittee, and the Defense Subcommittee on Appropriations. He also served on the Joint Committee on Atomic Energy and was instrumental in the location at Houston of the Manned Spacecraft Center (later the Lyndon B. Johnson Space Center) of the National Aeronautics and Space Agency. At the time of his death Thomas had risen to eleventh in seniority in the House of Representatives. In 1949 he became chairman of the House Subcommittee on Independent Office Appropriations, was elected chairman of the Texas House delegation in 1950, and was named chairman of the House Democratic caucus in 1964. While he was contemplating retiring from office because of ill health in 1963, President John F. Kennedy and Vice President Lyndon B. Johnson attended a testimonial dinner in Thomas's honor in Houston to urge that he remain in Congress. Kennedy was assassinated in Dallas the following day, and Thomas returned to Washington on the President's plane, Air Force One, with President Johnson. The photograph in which he appears as a witness to Johnson's oath of office is one of the most memorable pictures from that historic time. Thomas was a Methodist. He died on February 15, 1966, and was buried in Houston. His widow was elected to complete his unexpired term.
29° 55.828, -095° 27.080
Houston National Cemetery