Born Stephen Arnold Douglass in Brandon, Vermont, Douglas dropped the second "s" from his name some years later. He came to Illinois in 1833, was an itinerant teacher, studied law, and settled in Jacksonville. By the end of the year, he told his Vermont relatives, "I have become a Western man, have imbibed Western feelings principles and interests and have selected Illinois as the favorite place of my adoption." He served as Morgan County State's Attorney from 1834-36. Within a decade, he was elected to the state legislature, and was appointed registrar of the Springfield Land Office, Illinois Secretary of State, and an associate justice of the Illinois Supreme Court in 1841, at age 27. A leader of the majority Democratic Party, he was elected twice to Congress (1842 and 1844), where he championed expansion and supported the Mexican War. Elected by the legislature to the U.S. Senate in 1846, he was reelected in 1852 and 1858. He was challenged for his Senate position in 1858 by Abraham Lincoln, who had served with Douglas in the legislature, in a series of nationally famous debates which significantly boosted Lincoln's reputation despite his loss to Douglas.