of State Abel P. Upshur of Virginia to initiate, then relentlessly pursue, secret annexation talks with Texas minister to the United States Isaac Van Zandt, beginning on October 16, 1843. Tyler submitted his Texas-U.S. treaty for annexation to the U.S. Senate, delivered April 22, 1844, where a two-thirds majority was required for ratification. The newly appointed Secretary of State John C. Calhoun of South Carolina (assuming his post March 29, 1844) included a document known as the Packenham Letter with the Tyler bill that was calculated to inject a sense of crisis in Southern Democrats of the Deep South. In it, he characterized slavery as a social blessing and the acquisition of Texas as an emergency measure necessary to safeguard the "peculiar institution" in the United States. In doing so, Tyler and Calhoun sought to unite the South in a crusade that would present the North with an ultimatum: support Texas annexation or lose the South. Anti-slavery Whigs considered Texas annexation particularly egregious, since Mexico had outlawed slavery in Coahuila y Tejas in 1829, before Texas independence had been declared. The 1844 presidential campaigns evolved within the context of this struggle over Texas annexation, which was tied to the question of slavery expansion and national security. All candidates in the 1844 presidential election had to declare a position on this explosive issue. Nominations Democratic Party convention and campaign Martin Van Buren, President of the United States between 1837 and 1841, and chief architect of Jacksonian democracy, was the presumptive Democratic presidential contender in the spring of 1844. With Secretary of State John C. Calhoun withdrawing his bid for the presidency in January 1844, the campaign was expected to focus on domestic issues. All this changed with the Tyler treaty. Van Buren regarded the Tyler annexation measure as an attempt to sabotage his bid for the White House by exacerbating the already strained North-South Democratic alliance regarding slavery expansion. Calhoun's Packenham Letter would serve to spur Democrats of the South to the task of forcing the Northern wing of the party to submit to Texas annexation, despite the high risk of "aggressively injecting slavery into their political campaign over Texas." The annexation of Texas was the chief political issue of the day. Van Buren, initially the leading candidate, opposed immediate annexation because it might lead to a sectional crisis over the status of slavery in the West and lead to war