On September 24, 1945, Mathes was nominated by President
Harry S. Truman to a seat on the
United States District Court for the Southern District of California vacated by Judge
Ralph E. Jenney. Mathes was confirmed by the
United States Senate on October 11, 1945, and received his commission on October 17, 1945. He was a member of the
Judicial Conference of the United States from 1958 to 1960. He served as Chief Judge from 1964 to 1965, assuming
senior status on June 9, 1965. Mathes served in that capacity until his death on July 24, 1967.
Notable case Mathes was the trial judge in the case of
Kawakita v. United States, which eventually went before the
Supreme Court of the United States. ==Note==