When Alben Barkley resigned his Senate seat to assume the office of vice president in 1949, Clements had appointed Garrett L. Withers to fill the vacancy. Barkley's term was to expire in 1951, and near the end of the term, Withers resigned, allowing Clements to run in a special election to fill both the remainder of Withers' term and a full six-year term simultaneously. He won the election over Republican Charles I. Dawson by a vote of 300,276 to 256,876. On November 27, 1950, he resigned as governor to assume the seat.