Michael Perman, "Fessenden, William Pitt," American National Biography Online, February 2000, http://www.anb.org/articles/04/04-00371.html.
Although not an abolitionist like his controversial father, Fessenden disliked slavery and opposed its expansion. He very soon actively organized the Anti-Nebraska coalition in Maine and, in the summer of 1855, quit the Whig party to join the Republicans, "that great Northern movement which I believe to be essential to the future welfare of the country" (Jellison, p. 86). As a leading Republican in the Senate, Fessenden was in the forefront of the struggle to make Kansas a free state, and in the process he became Stephen Douglas's nemesis, forever challenging him in debate. Indeed, Douglas was forced to concede that, among the great orators of the mid-nineteenth century, such as Henry Clay, John C. Calhoun, and Webster, Fessenden was "the readiest and ablest debater" (Jellison, p. 95). In 1857 Fessenden contracted a form of malaria, and his health remained poor the rest of his life. In addition, his wife died in 1857. As a result of his prominent role in the forensic wrangling over the Lecompton constitution and his work on the Finance Committee, Fessenden was reelected in 1859 by a heavily Republican Maine legislature. After Abraham Lincoln's election, Fessenden was one of the most adamant Republicans in urging the administration to stand firm against southern threats to secede. Even after his state selected him to attend the Washington Peace Conference at Willard's Hotel in February 1861, he was so unwilling to consider concessions that he refused to attend.