his supporters in Congress began exploring means to bypass the supermajority requirement for Senate treaty approval. Substituting the constitutional protocols for admitting regions of the United States into the Union as states, Tyler proposed that alternative, yet constitutional, means be used to bring the Republic of Texas – a foreign country – into the Union. Tyler and Calhoun, formerly staunch supporters of minority safeguards based on the supermajority requirements for national legislation, now altered their position to facilitate passage of the Tyler treaty. Tyler's attempt to evade the Senate vote launched a spirited congressional debate. Whig Party convention and campaign Henry Clay of Kentucky, effectively the leader of the Whig Party since its inception in 1834, was selected as its nominee at the party's convention in Baltimore, Maryland, on May 1, 1844. Clay, a slaveholder, presided over a party in which its Southern wing was sufficiently committed to the national platform to put partisan loyalties above slavery expansionist proposals that might undermine its north–south alliance. Whigs felt confident that Clay could duplicate Harrison's landslide victory of 1840 against any opposition candidate. Southern Whigs feared that the acquisition of the fertile lands in Texas would produce a huge market for slave labor, inflating the price of slaves and deflating land values in their home states. Northern Whigs feared that Texas statehood would initiate the opening of a vast "Empire for Slavery". Two weeks before the Whig convention in Baltimore, in reaction to Calhoun's Packenham Letter, Clay issued a document known as the Raleigh Letter (issued April 17, 1844) that presented his views on Texas to his fellow southern Whigs. In it, he flatly denounced the Tyler annexation bill and predicted that its passage would provoke a war with Mexico, whose government had never recognized Texas independence. Clay underlined his position, warning that even with Mexico's consent, he would block annexation in the event that substantial sectional opposition existed anywhere in the United States. The Whig party leadership was acutely aware that any proslavery legislation advanced by its southern wing would alienate its anti-slavery northern wing and cripple the party in the general election. In order to preserve their party, Whigs would need to stand squarely against acquiring a new slave state. As such, Whigs were content to restrict their 1844 campaign platform to less divisive issues such as internal improvements and national finance. Whigs picked Theodore Frelinghuysen of New Jersey –