Regiment Tennessee Volunteer Cavalry under Colonel John K. Miller in late 1863. Butler received the rank of lieutenant colonel, and served until 1864, when he resigned for health reasons. Butler was a delegate to the Republican National Conventions in 1864, 1872 and 1876. In 1865, he was a delegate to the Tennessee state constitutional convention. That same year, he was elected to the Tennessee Senate, but resigned to accept an appointment by Governor William G. Brownlow as judge of the state's First Judicial Circuit Court. He was chairman of the first state Republican executive committee of Tennessee. He was also a delegate to the Baltimore Border State Convention in 1867. Postwar political endeavors In 1867, Butler was elected as a Republican to the Fortieth United States Congress, winning over 86% of the vote in a race against Democrat James White. He ran virtually unopposed in 1868. He was censured by the House of Representatives on March 17, 1870, for accepting payment in return for recommending the appointment of a cadet to West Point (a vote to expel failed). He was narrowly reelected later that year in a three-way race against White and former congressman Nathaniel Green Taylor. Though the state legislature gerrymandered his district, he was nevertheless reelected to a fourth term in 1872, winning 56% of the vote in a race against William B. Carter, the leader of the East Tennessee bridge-burning conspiracy. He was finally defeated for reelection in 1874, garnering just 44% of the vote against the Democratic candidate, William McFarland. During the 40th Congress (1867–1869), Butler served on the Committee on the Revision of Laws (now part of the Judiciary Committee). During the 41st Congress, he served on the Committee on Elections and the Committee on Revolutionary Pensions. For the 42nd Congress, he was a member of the Committee on Freedmen's Affairs, and for the 43rd Congress, he was a member of the Committee on Indian Affairs. In 1878, Butler was elected to the Tennessee House of Representatives, where he would serve until 1885. In 1887, Butler was again elected to Congress, defeating his old opponent, James White, with about 60% of the vote. In 1887, he failed to win his party's nomination for reelection, but ran in the general election as an Independent Republican. He was narrowly defeated by rising politician Alfred A. Taylor. In 1893, he was elected to the Tennessee Senate, where he