John Tyler entered Virginia politics as a lawyer and member of a prominent slaveholding family. He served in the state legislature, the United States House, the governorship, and the Senate. His political identity centered on states' rights and resistance to expansive federal authority. A former Democrat who broke with Andrew Jackson, he joined the Whigs without accepting every part of their economic program. The party selected him as William Henry Harrison's running mate in 1840.

Harrison's death in April 1841 made Tyler the first vice president to succeed after a president died in office. He asserted the full title and authority of president rather than acting only temporarily, establishing an important precedent. Conflict soon followed when he vetoed bills for a new national bank. Most of his cabinet resigned, and the Whigs expelled him from their party. He governed with little reliable congressional support, using appointments and vetoes while seeking a coalition that never fully developed.

Tyler's administration nevertheless achieved measures in foreign relations and government. The Webster-Ashburton Treaty of 1842 settled important boundary disputes with Britain, while the Treaty of Wanghia in 1844 established relations and commercial privileges in China. Annexation of Texas became his principal late objective. After a proposed treaty failed in the Senate, he supported annexation by joint resolution, signing the measure in 1845 before leaving office. Expansion intensified disputes over slavery and relations with Mexico, creating consequences that extended into the next presidency.

Tyler retired to his Virginia estate but remained involved in public questions. He chaired the unsuccessful Peace Conference in 1861 before supporting secession and the Confederacy. Elected to the Confederate House, he died in January 1862 before taking his seat. His career combined a clarification of presidential succession with persistent commitment to a slaveholding states' rights politics. The claim that he defended constitutional limits must be assessed alongside the people denied rights within the society he supported. His isolated presidency demonstrated that executive authority could survive a rupture with the party that elected it, but also exposed the difficulty of governing without an enduring legislative coalition. The treaties and annexation were concrete achievements, while their unequal terms and sectional effects remain part of the historical record.