gigantic rallies, parades, and rhetorical rabble-rousing. Rise, 1836–1841 Early successes in various states made many Whigs optimistic about victory in 1836, but an improving economy bolstered Van Buren's standing ahead of the election. The Whigs also faced the difficulty of uniting former National Republicans, Anti-Masons, and states' rights Southerners around one candidate, and the party suffered an early blow when Calhoun announced that he would refuse to support any candidate opposed to the doctrine of nullification. Northern Whigs cast aside both Clay and Webster in favor of General William Henry Harrison, a former senator who had led U.S. forces in the 1811 Battle of Tippecanoe. Though he had not previously been affiliated with the National Republicans, Harrison indicated that he shared the party's concerns over Jackson's executive power and favored federal investments in infrastructure. Southern Whigs coalesced around Senator Hugh Lawson White, a long-time Jackson ally who opposed Van Buren's candidacy. Ultimately, Van Buren won a majority of the electoral and popular vote in the 1836 election, though the Whigs improved on Clay's 1832 performance in the South and West. Shortly after Van Buren took office, an economic crisis known as the Panic of 1837 struck the nation. Land prices plummeted, industries laid-off employees, and banks failed. According to historian Daniel Walker Howe, the economic crisis of the late 1830s and early 1840s was the most severe recession in U.S. history until the Great Depression. Van Buren's economic response centered on establishing the Independent Treasury system, essentially a series of vaults that would hold government deposits. As the debate over the Independent Treasury continued, William Cabell Rives and some other Democrats who favored a more activist government defected to the Whig Party, while Calhoun and his followers joined the Democratic Party. Whig leaders agreed to hold the party's first national convention in December 1839 in order to select the Whig presidential nominee. By early 1838, Clay had emerged as the front-runner due to his support in the South and his spirited opposition to Van Buren's Independent Treasury. A recovering economy convinced other Whigs to support Harrison, who was generally seen as the Whig candidate best able to win over Democrats and new voters. With the crucial support of Thaddeus Stevens of Pennsylvania and Thurlow Weed of New York, Harrison won the presidential nomination on the fifth ballot of the 1839 Whig National Convention. For vice president, the Whigs nominated John