Bourne was a member of the
Oregon House of Representatives from 1885 to 1886, representing
Multnomah County. He returned to the House in 1897, representing District 37 and Multnomah County as a Republican, and only served during the regular session that failed to organize that year. In 1906, he was elected as a Republican to the U.S. Senate, becoming one of the first two senators to be elected under Oregon's
direct primary law, in which senators were selected by popular vote, and then were officially elected to the position by the
Oregon Legislative Assembly to comply with
Article One of the U.S. Constitution. (In 1914, the
17th Amendment established direct election of senators.) He served from March 4, 1907, to March 3, 1913. In 1911-1912 Bourne served as president of the National Republican Progressive League. He organized the Republican Publicity Association in 1912. Bourne was not renominated to his Senate seat in 1912 by the Republican Party, ==Later life and legacy==