[188] He attempted to win ratification of an annexation treaty in 1844, but, to Adams's surprise and relief, the Senate rejected the treaty.[189] The annexation of Texas became the central issue of the 1844 presidential election, and Southerners blocked the nomination of Van Buren at the 1844 Democratic National Convention due to the latter's opposition to annexation; the party instead nominated James K. Polk, an acolyte of Andrew Jackson.[190] Though he once again did not take part in the campaigning, Adams was deeply disappointed that Polk defeated his old ally, Henry Clay, in the 1844 election. He attributed the outcome of the election partly to the Liberty Party, a small, abolitionist third party that may have siphoned votes from Clay in the crucial state of New York.[191] After the election, Tyler, whose term would end in March 1845, once again submitted an annexation treaty to Congress.[e] Adams strongly attacked the treaty, arguing that the annexation of Texas would involve the United States in "a war for slavery". Despite Adams's opposition, both houses of Congress approved the treaty, with most Democrats voting for annexation and most Whigs voting against it. 