Texas annexation remained on the political back burner until President John Tyler revived it in the hope of rescuing his failed administration and securing southern support for renomination in 1844. In April 1844, a letter by John C. Calhoun, whom Tyler had appointed secretary of state, was leaked to the press. It linked the idea of absorbing Texas directly to the goal of strengthening slavery in the United States. Some southern leaders, indeed, hoped that Texas could be divided into several states, thus further enhancing the South’s power in Congress. Late that month, Henry Clay and former president Van Buren, the prospective Whig and Democratic candidates for president and two of the party system’s most venerable leaders, met at Clay’s Kentucky plantation. They agreed to issue letters rejecting immediate annexation on the grounds that it might provoke war with Mexico. Clay and Van Buren were reacting to the slavery issue in the traditional manner—by trying to keep it out of national politics.
Clay went on to receive the Whig nomination, but for Van Buren the letters proved to be a disaster. At the Democratic convention, southerners bent on annexation deserted Van Buren’s cause, and he failed to receive the two-thirds majority necessary for nomination. The delegates then turned to the little-known James K. Polk, a former governor of Tennessee whose main assets were his support for annexation and his close association with Andrew Jackson, still the party’s most popular figure. Like nearly all the presidents before him, Polk was a slaveholder. He owned substantial cotton plantations in Tennessee and Mississippi, where conditions were so brutal that only half of the slave children lived to the age of fifteen, and adults frequently ran away. To soothe injured feelings among northern Democrats over the rejection of Van Buren, the party platform called not only for the “reannexation” of Texas (implying that Texas had been part of the Louisiana Purchase and therefore once belonged to the United States) but also the “reoccupation” of all of Oregon. “Fifty-four forty or fight”—American control of Oregon all the way to its northern boundary at north latitude 54°40`—became a popular campaign slogan. But the bitterness of the northern Van Burenites over what they considered to be a betrayal on the part of the South would affect American politics for years to come.
Polk was the first “dark horse” candidate for president—that is, one whose nomination was completely unexpected. In the fall, he defeated Clay in an extremely close election. Polk’s margin in the popular vote was less than 2 percent. Had not James G. Birney, running again as the Liberty Party candidate, received 16,000 votes in New York, mostly from antislavery Whigs, Clay would have been elected. In March 1845, only days before Polk’s inauguration, Congress declared Texas part of the United States.