U.S. House of Representatives (1937–1951)

Case entered politics in 1934 when he ran for a seat in the United States House of Representatives but lost. In 1936, however, he was elected to the U.S. House and served in it for seven terms. Before the United States entered World War II, he was a moderate supporter of isolationism. In 1947–8, he served on the Herter Committee.^[2] Case left the House in 1951 when he became a senator.

U.S. Senate (1951–1962)

Case decided to run for the Senate in the 1950 election, and defeated the incumbent John Chandler Gurney in the Republican primary. In the general election, he easily defeated Democrat John A. Engel receiving 63% of the vote. In his first term in the Senate, he served as chairman of the United States Senate Committee on the District of Columbia from 1953 to 1955, and was a supporter of greater self-rule in the district. In 1954, he served on a committee to investigate censuring Senator Joseph McCarthy. Case was reelected to the Senate in 1956, in a very close race against Democrat Kenneth Holum, receiving 50.8% of the vote.

Case was known as a moderate senator whose main goals were to expand America's road and waterway infrastructure, particularly in South Dakota. Lake Francis Case, along the Missouri River, is named after him, as is a bridge on I-395 in Washington, D.C. Case voted in favor of the Civil Rights Acts of 1957 and 1960,^[3][4] but did not vote on the 24th Amendment to the U.S. Constitution.^[5]

Case served in the Senate from 1951 until his death. He died of a heart attack at the Naval Hospital in Bethesda, Maryland, on June 22, 1962. His death occurred several months before the expiration of his second term in the Senate. he was buried at Black Hills National Cemetery in Sturgis.