David Worth Clark (April 2, 1902 – June 19, 1955) was a Democratic congressman and United States Senator from Idaho, its first U.S.

Clark ran for the U.S. Senate in 1938 and narrowly won the Democratic primary in August over incumbent James Pope of Boise, a setback for New Deal supporters.

[6] Welker aligned himself in the Senate with the infamous Joseph McCarthy of Wisconsin and lost his re-election bid in 1956 to 32 year-old Frank Church of Boise (husband of Clark's cousin, Bethine), who served four terms.

He moved to Los Angeles in 1954 and held financial interests in radio stations in Van Nuys, San Francisco, and Honolulu, and a bank in Las Vegas.

Clark's wife Virgil (1901–1991) was a sister-in-law of Robert Smylie; the three-term (1955–1967) Republican governor of Idaho married her younger sister Lucile.