Douglas began practicing law in 1834, followed quickly by political ventures, including the office of Illinois attorney general. In 1840, Douglas became Illinois secretary of state, then served as a judge on the state supreme court from 1841 to 1843. He was elected to the House of Representatives in 1843 and to the Senate in 1847.
Douglas played a major role in most of the major public issues of his day. He was an ardent expansionist, advocating the annexation of Cuba and the entirety of the Oregon Territory. In the Senate Douglas chaired the influential Committee on Territories. With Henry
Clay he drafted the component bills of the Compromise of 1850. Douglas coined the term “popular sovereignty” and urged that doctrine's acceptance as a solution to the problems of the extension of slavery in the territories. He also was the prime force behind the Kansas-Nebraska Act in 1854.
Douglas was nominated for president by the Democratic Party in 1852 and 1856. In the latter campaign, Douglas threw his support to James Buchanan, the eventual winner. In one of the most dramatic and principled moves of his career, In 1858 he went up for re-election to the Senate and engaged Abraham Lincoln in the Lincoln-Douglas Debates. Douglas won the election, but Lincoln emerged as a national figure. In 1860 Douglas was unable to secure the necessary two-thirds vote for nomination in the Democratic convention, but later accepted nomination from the Northern Democrats.
Douglas worked tirelessly in search of a compromise that might avert war. But when conflict arose with the southern states, he supported lincoln without question. Later on his trip to the midwest and the coastal states he contracted typhoid and died in 1861. Leaving behind a legacy that the modern democratic party still follows today.