He remained in this position until 1924, when he resigned to accept the Democratic nomination for the United States Senate.

[1][2] Bratton was elected as a Democrat to the United States Senate in 1924 and was reelected in 1930 and served from March 4, 1925, until his resignation, effective June 24, 1933.

[1] Bratton was nominated by President Franklin D. Roosevelt on June 1, 1933, to a seat on the United States Court of Appeals for the Tenth Circuit vacated by Judge John Hazelton Cotteral.

He was among the candidates for the United States Supreme Court vacancy created by the retirement of Willis Van Devanter in 1937, but was passed over by Roosevelt in favor of Hugo Black.

[3] Bratton served as Chief Judge and as a member of the Judicial Conference of the United States from January 1, 1956 to August 7, 1959.