During the Mexican War, in 1846, a bill was introduced to allocate 2 million dollars for the negotiation of a territorial settlement. The Wilmot Proviso was an amendment to this bill, which required that slavery not be practiced in any new territory. The bill passed in the House of Representatives but stalled in the Senate, and was a major source of controversy between the North and the South. The text of the bill is as follows:
"Provided. That, as an express and fundamental condition to the acquisition of any territory from the Republic of Mexico by the United States, by virtue of any treaty which may be negotiated between them, and to the use by the Executive of the moneys herein appropriated, neither slavery nor involuntary servitude shall ever exist in any part of said territory, except for crime, whereof the party shall first be duly convicted."
Increasing animosity between North and South over whose vision of America's future would prevail is an important element of the context for Leaves of Grass. This reveals that Whitman's description of sheltering a fugitive slave was a radical political statement in his time, but also that a significant population of Americans objected to slavery and were a ripe audience for his assertions of equality.
"Wilmot Proviso." Columbia Electronic Encyclopedia, 6th Edition (2011): 1. Academic Search Complete. Web. 26 Jan. 2012.
"Wilmot Proviso, 1846." Wilmot Proviso, 1846 (2009): 1. Academic Search Complete. Web. 26 Jan. 2012