To what extent did political parties contribute to the development of national unity in the United States between 1790 and 1840?
The nature of political parties changed considerably during this period. In 1790 to the aftermath of the War of 1812, it is perhaps most accurate to say that the Federalists and the Republicans reflected the divisions that characterized American politics. Each party held a very different vision for the new nation. However, throughout this period, it could be said that parties contributed to sectional unity, as neither of the major parties of the period drew exclusively from the North or South. Shortly after the end of the period in question, however, the cross-sectional alliances that stitched together the major parties showed signs of stress.
The aftermath of the war saw a period of broad consensus that was reflected in the decline of the Federalists. Until the emergence of Andrew Jackson as a national political figure in 1824, party division was virtually nonexistent. Yet sectional tensions over the expansion of slavery, reflected in the debate over Missouri, were quite potent and dangerous. The election of 1824, which saw John Quincy Adams chosen president in the House of Representatives, essentially ushered in what historians call the "second party system." In the wake of this election, Jackson emerged, with Martin Van Buren close behind, as the leader of a Democratic Party that brought in many Southerners as well as Northerners, especially in Van Buren's New York. Jackson's appeal resonated with an expanding white electorate, and, some historians have argued, appealed to those disaffected by the economic changes (known as the market revolution) that characterized the period. Jackson's position on the bank was especially popular among these people.
During the late 1820s into the 30s, the parties reflected a fundamental disagreement over the role of government in economic expansion as well as a host of other issues. By 1836, the Whig Party had emerged as a coalition of politicians who disapproved of Jackson's actions against the National Bank as well as a host of other actions. By 1840, they won the White House with William Henry Harrison (though he quickly died and was replaced by John Tyler, whose actions were decidedly anti-Whig). By this point, sectional tensions began to pull at the parties even as they coalesced into something like the disciplined organizations they are today.