for the Democratic nomination for the state Senate from the 6th district in 1966, but placed third behind Bill Pearce and L. P. Gibson. In 1967, he ran for the Democratic nomination for the state House of Representatives from the 11th district. In the primary he defeated incumbent Representative Coy J. Mitchell and later faced no opposition in the general election. In 1968 and 1970, he won reelection. On June 29, 1972, he announced that he would seek reelection to the House of Representatives. In the Democratic primary he defeated John Grace, a 26 year old veteran of the Vietnam War, and in the general election Mixson faced no opposition. In 1974, he was reelected. Tenure During the 1967–1968 session of the House of Representatives Mixson served on the Ad Valorem Taxation, Appropriations, Claims, Public Health and Welfare, and State Institutions committees. During the 1968–1970 session of the House of Representatives he served as the vice chairman of the Agriculture committee and as a member of the Ad Valorem Taxation, and Transportation committees. During the 1970–1972 session of the House of Representatives he served as the vice chairman of Community Affairs committee and as a member of the Agriculture, Appropriations, and Migrant Affairs committees. In 1971, Mixson was selected to serve as a Majority Whip alongside John Clark, Elvin L. Martinez, Roy Hess, Ed Fortune, John Forbes, Lew Whitworth, and Harold Featherstone. Each whip was placed in charge of ten of the eighty-one Democratic members of the House. During the 1972 Democratic presidential primaries he supported Senator Henry M. Jackson. In January 1972, Mixson was selected by Speaker Richard Pettigrew to replace Howell Lancaster as chairman of the Agriculture committee due to Lancaster's death. During the 1973–1975 session of the House of Representatives he served as the chairman of Agriculture committee and as a member of the Rules, and Community Affairs committees. In 1973, an impeachment inquiry was held for Lieutenant Governor Thomas Burton Adams Jr. for using public employees for personal financial gain during his service as Secretary of Commerce. On May 17, the House of Representatives voted 61 to 55 in favor of impeaching Adams, but needed a two-thirds majority of 78 to impeach him. Mixson had voted against impeaching. After failing to impeach Adams the House of Representatives voted 88 to 26 in favor of censuring Adams for using the office for personal gain, which Mixson voting