1861'den 1865'teki suikastına kadar, Abraham Lincoln ABD Başkanıydı.
Lincoln was elected to the United States Congress in 1846. His career got off to a rocky start because he was a vocal opponent of the Mexican War and claimed that slavery should be abolished. Both of these views were unpopular in his Illinois district, and he did not win re-election. Lincoln practiced law for the next 12 years, growing his business. With a bill introduced by Stephen Douglas to organise the Kansas-Nebraska Territory in 1854, the controversial question of slavery exploded. This bill enraged Lincoln so much that he returned to politics. After failing to win a senatorial nomination in 1855, Lincoln joined the new Republicans, believing his former faction, the Whigs, were effectively dead, and became a leading figure in the party.