Americans began the War of 1812 with high hopes of conquering Canada. But their strategy and efforts were badly flawed, and before long British and Canadian forces had thrown the United States on the defensive. The Americans fared somewhat better in naval warfare, but by 1814 the British had burned Washington and were threatening New Orleans. The Treaty of Ghent ended the war in a stalemate that solved none of the original issues. But Americans counted the war a success and increasingly turned away from European affairs and toward isolationism.

Despite some secessionist talk by New Englanders at the Hartford Convention, the ironic outcome of the divisive war was a strong surge of American nationalism and unity. Political conflict virtually disappeared during the Era of Good Feelings under President Madison. A fervent new nationalism appeared in diverse areas of culture, economics and foreign policy.

The Era of Good Feelings was soon threatened by the Panic of 1819, caused largely by excessive land speculation and unstable banks. An even more serious threat came from the first major sectional dispute over slavery, which was postponed but not really resolved by the Missouri Compromise of 1820.

Under Chief Justice John Marshall, the Supreme Court further enhanced its role as the major force upholding a powerful national government and conservative defense of property rights. Marshalls rulings partially checked the general movement toward states rights and popular democracy.

Nationalism also led to a more assertive American foreign policy. Andrew Jacksons military adventures in Spanish Florida resulted in the cession of that territory to the U.S. American fears of European intervention in Latin America encouraged Monroe and J. Q. Adams to lay down the Monroe Doctrine.