Despite his low regard for Harrison as a person, Adams was enthusiastic about the new Whig administration and the end of the long-standing Democratic dominance of the federal government.[186] However, Harrison died in April 1841 and was succeeded by Vice President John Tyler, a Southerner who, unlike Adams, Henry Clay, and many other prominent Whigs, did not embrace the American System. Adams saw Tyler as an agent of "the slave-driving, Virginia, Jeffersonian school, principled against all improvement". After Tyler vetoed a bill to restore the national bank, Whig congressmen expelled Tyler from the party. Adams was appointed chairman of a special committee that explored impeaching Tyler, and Adams presented a scathing report of Tyler that argued that his actions warranted impeachment. The impeachment process did not move forward, though, because the Whigs did not believe that the Senate would vote to remove Tyler from office.[187]

John Quincy Adams, c. 1840s, Unknown author
Opposition to the Mexican-American War, 1844–1848
Tyler made the annexation of Texas the main foreign policy priority of the later stages of his administration.