[82] Nevertheless, because of the opposition to Van Buren by expansionists in the West and South, Polk's key lieutenant at the 1844 Democratic National Convention in Baltimore, Gideon Johnson Pillow, believed Polk could emerge as a compromise candidate.[83] Publicly, Polk, who remained in Columbia during the convention, professed full support for Van Buren's candidacy and was believed to be seeking the vice presidency. Polk was one of the few major Democrats to have declared for the annexation of Texas.[84]
The convention opened on May 27, 1844. A crucial question was whether the nominee needed two-thirds of the delegate vote, as had been the case at previous Democratic conventions, or merely a majority. A vote for two-thirds would doom Van Buren's candidacy due to the opposition to him.[85] With the support of the Southern states, the two-thirds rule was passed.[86] Van Buren won a majority on the first presidential ballot but failed to win the necessary two-thirds, and his support slowly faded on subsequent ballots.[86] Cass, Johnson, Calhoun and James Buchanan had also received votes on the first ballot, and Cass took the lead on the fifth ballot.