The presidency of John Tyler began on April 4, 1841, when John Tyler became President of the United States upon the death of President William Henry Harrison, and ended on March 4, 1845. The treaty clearly delineated Maine's Northern border, as well as other sections of the U.S.-Canada border that had been in dispute. The treaty also included a pledge by the United States to step up enforcement against the Atlantic slave trade.Senator Thomas Hart Benton led Senate opposition to the treaty, arguing that it 'needlessly and shamelessly' relinquished American territory, but few others joined Benton in resisting the treaty.