What US senator was responsible for the anti Communist movement known as the red Scare?

Joseph McCarthy, a Republican senator from Wisconsin who served in Congress from 1947 until his death in 1957.

He used his position as chairman of the Committee on Government Operations and its Permanent Subcommittee on Investigations to launch investigations designed to document charges of Communists in government and was censured by the Senate on December 2, 1954, for behavior that was "contrary to senatorial traditions."

See Biographical Dictionary of the United States Congress