The people of Texas actively pursued joining the Union, but Jackson and Van Buren had been reluctant to inflame tensions over slavery by annexing another Southern state. Though Tyler intended annexation to be the focal point of his administration, Secretary Webster was opposed, and convinced Tyler to concentrate on Pacific initiatives until later in his term.[140] Tyler's desire for western expansionism is acknowledged by historians and scholars, but views differ regarding the motivations behind it. Biographer Edward C. Crapol notes that during the presidency of James Monroe, Tyler (then in the House of Representatives) had suggested slavery was a "dark cloud" hovering over the Union, and that it would be "well to disperse this cloud" so that with fewer blacks in the older slave states, a process of gradual emancipation would begin in Virginia and other upper Southern states.[141] Historian William W. Freehling, however, wrote that Tyler's official motivation in annexing Texas was to outmaneuver suspected efforts by Great Britain to promote an emancipation of slaves in Texas that would weaken the institution in the United States.[142]

Early attempts
The boundaries of the United States and neighboring nations as they appeared in 1843. 