Historians have generally ranked John Tyler as one of the least successful chief executives, despite achievements such as the WebsterAshburton treaty, which heralded improved relations with Great Britain, and the annexation of Texas. Why did Tyler pursue what appears to have been a politically selfdestructive course with regard to both his first party, the Democrats, and his later political alliance, the Whigs? Monroe has set out to explain the beliefs that led to Tyler=s resigning his Senate seat and exercising politically suicidal presidential vetoes as well as examines the crises Tyler faced during his term in the House: the Panic of 1819, the financially tottering national bank, and the Missouri debate.