First page of a letter from President Jimmy Carter to Julian Nava, April 3, 1980. In April 3, 1980 Julian Nava became the first Mexican-American appointed U.S. Ambassador to Mexico under the Carter Administration. When President Carter was not re-elected in 1980, the Reagan administration declined to keep Nava in his position and instead informed Nava that his successor had been selected. Julian Nava Collection. Latino Cultural Heritage Digital Archives.