Private practice, Wichita, 1955-1963. Partner firm McCarter, Frizzell & Wettig, 1963-1968. Member Kansas Senate, 1965-1969.
Attorney general Kansas, 1969-1971. Assistant attorney general Land and Natural Resources division United States Department Justice, Washington, 1972-1973. Solicitor Department Interior, 1973-1975, undersecretary, 1975-1976.
Director National Energy Law and Policy Institute University Tulsa, 1976-1994. Professor emeritus University Tulsa, 1995. Chief government negotiator Wounded Knee, South Dakota, 1973.
Member National Petroleum Council, 1977-1979. Member Barteltt Council of Energy Security, Center for Strategic and International Studies, Washington, 1984-1989. Member National Advisory Board Washington Legal Foundation, since 1986.
Member, board trustees William Allen White Foundation, University Kansas, 1987-1990.