He was elected vice president on the 1840 Whig ticket with President William Henry Harrison, succeeding to the presidency following Harrison's death 31 days after assuming office. Tyler was a stalwart supporter and advocate of states' rights, including regarding slavery, and he adopted nationalistic policies as president only when they did not infringe on the states' powers. His unexpected rise to the presidency posed a threat to the presidential ambitions of Henry Clay and other Whig politicians and left Tyler estranged from both of the nation's major political parties at the time.
Tyler was born into a prominent slaveholding Virginia family. He became a national figure at a time of political upheaval. In the 1820s, the nation's only political party was the Democratic-Republican Party, and it split into factions. Initially a Democrat, Tyler opposed President Andrew Jackson during the nullification crisis as he saw Jackson's actions as infringing on states' rights and criticized Jackson's expansion of executive power during the Bank War. This led Tyler to ally with the Whig Party. He served as a Virginia state legislator and governor, U.S. representative, and U.S. senator. Tyler was a regional Whig vice-presidential nominee in the 1836 presidential election; they lost. 