on May 26, 1925. In 1878 he served in the Linn County Rifles, a volunteer militia formed to fight against belligerents from the Bannock, Shoshone, and Paiute peoples in the so-called Bannock War. Political career A member of the Democratic Party, Chamberlain ran for the Oregon House of Representatives in November 1880, winning election to a two-year term. In 1884, Chamberlain was named district attorney for Oregon's 3rd judicial district. His skill in that position gained the notice of Democratic Governor Sylvester Pennoyer and when in 1891 the state legislature established the new position of Oregon Attorney General, Chamberlain was appointed in May as the first to serve that position. He stood for election to the position in the fall, winning at the polls despite being the candidate of the minority party in the state. Chamberlain would remain Oregon's Attorney General until January 1895, following the expiration of his term. He would be the only Democrat to serve that position for 58 years, until Robert Y. Thornton was elected in 1952. After leaving the Oregon Attorney General's position, Chamberlain went into the banking business, taking positions with the First National Bank and later the Linn County National Bank in his new hometown of Albany. Chamberlain next moved north to Portland and in 1900 stood for election as the district attorney for Multnomah County. He won by more than 1,000 votes, despite the county's 4,000 vote Republican majority. This again put Chamberlain in the public eye for a run at statewide office. Governor of Oregon In 1902, he was nominated by the Democratic Party of Oregon for Governor by acclamation at the party's nominating convention. Chamberlain was elected Governor of Oregon in a tight election by just 256 votes, this in a state which delivered 15,000 more votes to the Republicans in the concurrent congressional elections. Chamberlain was reelected in 1906, resigning his term when elected to the Senate. United States Senator In 1908 he was elected as a Democrat to the U.S. Senate; he was reelected in 1914 and served from March 4, 1909, to March 3, 1921. He was an unsuccessful candidate for reelection in 1920. He was chairman of the Committee on Geological Survey (Sixty-second Congress) and a member of the Committee on Military Affairs (Sixty-third through Sixty-fifth Congresses), the Committee on Public Lands (Sixty-third Congress), and the Committee on Expenditures in the War Department (Sixty-sixth Congress). The