The United States underwent dramatic changes during the period of Democratic-Republican (also called Jeffersonian Republican, or simply Republican) political leadership in the first decades of the 19th century. The republic's expansion to the west and renewed military conflict with Indian nations and Great Britain each posed a fundamental challenge to the fragile new republic. All three of these factors played a role in the coming of the War of 1812.

The Louisiana Purchase of 1803 intensified American migration to the west that was already well underway. Anglo-American settlement in the 18th century had largely been confined to the eastern seaboard. It made its boldest inroads where rivers allowed easy internal transportation. As a result the chief population centers of early North America were clustered on the coast or along its major inland waterways.

While western movement and policies were reshaping the republic, European wars also presented a major challenge to the new country. The Napoleonic Wars (1802-1815) were a continuation of the conflict begun in the 1790s when Great Britain lead a coalition of European powers against Revolutionary France, though France was now led by the brilliant military strategist Napoleon Bonaparte. As had also been true in the 1790s, neither European superpower respected the neutrality of the United States. Instead, both tried to prevent U.S. ships from carrying goods to their enemy. Both Britain and France imposed blockades to limit American merchants, though the dominant British navy was clearly more successful.

In the 16th, 17th, and 18th centuries, the first white settlers in America inhabited the eastern seaboard. There the whites either made treaties with the Native American groups to buy land or they forcibly took Indian land. By the Revolution's end and on into the early 19th century, Native Americans were being displaced across the Appalachians and toward what is today the Midwest. For these exiled groups, there were few places left to go.

In the War of 1812 the United States once again fought against the British and their Indian allies. Some historians see the conflict as a Second War for American Independence.

The War of 1812 came to an end largely because the British public had grown tired of the sacrifice and expense of their twenty-year war against France. Now that Napoleon was all but finally defeated, the minor war against the United States in North America lost popular support. Negotiations began in August 1814 and on Christmas Eve the Treaty of Ghent was signed in Belgium. The treaty called for the mutual restoration of territory based on pre-war boundaries and with the European war now over, the issue of American neutrality had no significance.

The United States changed dramatically in its first half century. In 1776 the U.S. consisted of thirteen colonies clustered together on the eastern seaboard. By 1821 eleven new states had been added from Maine to Louisiana. This geographic growth and especially the political incorporation of the new states demonstrated that the United States had resolved a fundamental question about how to expand. This growth not only built upon the Louisiana Purchase, but included military intervention in Spanish Florida which the United States then claimed by treaty in 1819.

The transition from an agricultural to an industrial economy took more than a century in the United States, but that long development entered its first phase from the 1790s through the 1830s. The Industrial Revolution had begun in Britain during the mid-18th century, but the American colonies lagged far behind the mother country in part because the abundance of land and scarcity of labor in the New World reduced interest in expensive investments in machine production. Nevertheless, with the shift from hand-made to machine-made products a new era of human experience began where increased productivity created a much higher standard of living than had ever been known in the pre-industrial world.

The American Industrial Revolution, concentrated in the northeast, would ultimately prove to be the most significant force in the development of the modern United States. This economic innovation sprung primarily from necessity. New England's agricultural economy was the poorest in the country and that helped to spur experimentation there. Meanwhile, the far more fertile southern states remained fully committed to agriculture as the central source of its wealth, here, too, dramatic changes created a wholly new economy that would have been unrecognizable to late-18th century Americans.

In part because religion was separated from the control of political leaders, a series of religious revivals swept the United States from the 1790s and into the 1830s that transformed the religious landscape of the country. Known today as the Second Great Awakening, this spiritual resurgence fundamentally altered the character of American religion. At the start of the Revolution the largest denominations were Congregationalists (the 18th-century descendants of Puritan churches), Anglicans (known after the Revolution as Episcopalians), and Quakers. But by 1800, Evangelical Methodism and Baptists, were becoming the fasting-growing religions in the nation.

The breadth and success of the Second Great Awakening meant that it had multiple dimensions. Its origins in the 1790s had been especially radical and included strong commitments to anti-slavery among Methodists and Baptists. This radicalism quickly passed and even its populist elements tended to fade, or was most fully expressed in more egalitarian western locations. In urban areas the social movement also had a major impact, but here it tended to have a more conservative and institutional character that grew from the increasing distance between rich and poor created by the rapid economic growth of the early Industrial Revolution.

The social forces transforming the new nation had an especially strong impact on white women who, of course, could be found in families of all classes throughout the nation. As we have seen, the early Industrial Revolution began in the United States by taking advantage of young farm girls' labor. Meanwhile, the Second Great Awakening was largely driven forward by middle-class women who were its earliest converts and who filled evangelical churches in numbers far beyond their proportion in the general population. Furthermore, the Benevolent Empire included an institutional place for respectable women who formed important women's auxiliaries to almost all of the new Christian reform organizations.

American intellectuals and artists recognized the need for American cultural independence. In 1780s, Noah Webster declared that "America must be as independent in literature as she is in politics" His own major contribution to American cultural independence came through an immensely influential spelling book to standardize the American language. By the 1830s over 60 million copies had been sold and its descendent, Webster's dictionary, remains a mainstay of American bookshelves.

The social forces that reshaped the United States in its first half century were profound. Western expansion, growing racial conflict, unprecedented economic changes linked to the early Industrial Revolution, and the development of a stronger American Protestantism in the Second Great Awakening all overlapped with one another in ways that were both complementary and contradictory.

The 1818 Congressional election brought another landslide victory for Democratic-Republicans who controlled 85 percent of the seats in the U.S. Congress. James Monroe, yet another Virginian, followed Madison in the Presidency for two terms from 1817 to 1825. Although this period has often been called the Era of Good Feelings due to its one-party dominance, in fact, Democratic-Republicans were deeply divided internally and a new political system was about to be created from the old Republican-Federalist competition that had been known as the First Party System.

The rise of political parties as the fundamental organizing unit of the Second (Two) Party System represented a sharp break from the values that had shaped Republican and Federalist political competition. Leaders in the earlier system remained deeply suspicious that parties could corrupt and destroy the young republic. At the heart of the new legitimacy of parties, and their forthright celebration of democracy, was the dramatic expansion of voting rights for white men.

The contradictions inherent in the expansion of white male voting rights can also be seen in problems raised by western migration. The new western states were at the forefront of more inclusive voting rights for white men, but their development simultaneously devastated the rights of Native American communities. Native American rights rarely became a controversial public issue. This was not the case for slavery, however, as northern and southern whites differed sharply about its proper role in the west.

The 1824 presidential election marked the final collapse of the Republican-Federalist political framework. For the first time no candidate ran as a Federalist, while five significant candidates competed as Democratic-Republicans. Clearly, no party system functioned in 1824. The official candidate of the Democratic-Republicans to replace Monroe was William H. Crawford, the secretary of the treasury. A caucus of Republicans in Congress had selected him, but this backing by party insiders turned out to be a liability as other candidates called for a more open process for selecting candidates.

Like his father who was also a one-term president, John Quincy Adams was an intelligent statesman whose strong commitment to certain principles proved to be liabilities as president.

The presidential election of 1828 brought a great victory for Andrew Jackson. Not only did he get almost 70 percent of the votes cast in the electoral college, popular participation in the election soared to an unheard of 60 percent. This more than doubled the turnout in 1824; Jackson clearly headed a sweeping political movement. His central message remained largely the same from the previous election, but had grown in intensity. Jackson warned that the nation had been corrupted by "special privilege," characterized especially by the policies of the Second Bank of the United States.