Editing Horace Mann (section)

==A Whig in Congress==
In the spring of 1848, he was elected to the [[United States Congress]] as a [[Whig Party (United States)|Whig]] to fill the vacancy caused by the death of [[John Quincy Adams]]. His first speech in that role was in advocacy of its right and duty to exclude [[slavery]] from the territories, and in a letter, in December of that year, he said: "I think the country is to experience serious times. Interference with slavery will excite civil commotion in the South. But it is best to interfere. Now is the time to see whether the Union is a rope of sand or a band of steel."<ref>{{Cite book|last=Mann|first=Horace|title=Speech of Horace Mann, on the right of Congress to legislate for the territories of the United States, and its duty to exclude slavery therefrom|publisher=William B. Fowle|year=1848|location=Boston}}</ref> Again he said: "I really think if we insist upon passing the [[Wilmot Proviso|Wilmot proviso]] for the territories that the south—a part of them—will rebel; but I would pass it, rebellion or not. I consider no evil so great as the extension of slavery."<ref>James Ford Rhodes, ''History of the United States from the Compromise of 1850 to the Mckinley-Bryan Campaign of 1896'' (1892) vol 1, Page 132. [https://archive.org/details/1850historyofus01rhoduoft/page/n5/mode/2up?q=%22If+we+insist%22 online]</ref>

During the first session, he volunteered as counsel for [[Pearl incident|Drayton and Sayres]], who were indicted for stealing 76 slaves in the [[District of Columbia]], and at the trial was engaged for 21 successive days in their defense. In 1850, he was engaged in a controversy with [[Daniel Webster]] concerning the extension of slavery and the [[Fugitive Slave Law]], calling Webster's support for the [[Compromise of 1850]] a "vile catastrophe", and comparing him to "Lucifer descending from Heaven".<ref>{{Cite web|url=https://www.senate.gov/artandhistory/history/minute/Speech_Costs_Senator_His_Seat.htm|title=U.S. Senate: Speech Costs Senator His Seat|access-date=March 20, 2018|archive-date=December 10, 2017|archive-url=https://web.archive.org/web/20171210015521/https://www.senate.gov/artandhistory/history/minute/Speech_Costs_Senator_His_Seat.htm|url-status=live}}</ref><ref>{{cite book|last=Kennedy|title=Profiles in Courage| year=2004| pages=69–70}}</ref> Mann was defeated by a single vote at the ensuing nominating convention by Webster's supporters; but, on appealing to the people as an independent anti-slavery candidate, he was re-elected, serving from April 1848 until March 1853.