War of 1812, armed conflict between the United States and Great Britain, 1812?15. It followed a period of great stress between the two nations as a result of the treatment of neutral countries by both France and England during the French Revolutionary and Napoleonic Wars, in which the latter two were antagonists (1793?1801, 1803?14).

Causes of the War
American shippers took advantage of the hostilities in Europe to absorb the carrying trade between Europe and the French and Spanish islands in the West Indies. By breaking the passage with a stop in a U.S. port, they evaded seizure under the British rule of 1756, which forbade to neutrals in wartime trade that was not allowed in peacetime. In 1805, however, in the Essex Case, a British court ruled that U.S. ships breaking passage at an American port did not circumvent the prohibitions set out in the rule of 1756. As a result the seizure of American ships by Great Britain increased.

The following year Great Britain instituted a partial blockade of the European coast. The French emperor, Napoleon I, retaliated with a blockade of the British Isles. Napoleon's Continental System, which was intended to exclude British goods or goods cleared through Britain from countries under French control, and the British orders in council (1807), which forbade trade with France except after touching at English ports, threatened the American merchant fleet with confiscation by one side or the other. Although the French subjected American ships to considerable arbitrary treatment, the difficulties with England were more apparent. The impressment of sailors alleged to be British from U.S. vessels was a particularly great source of anti-British feeling, a famous incident of impressment being the Chesapeake affair of 1807.

Despite the infringement of U.S. rights, President Jefferson hoped to achieve a peaceful settlement with the British. Toward this end he supported a total embargo on trade in the hope that economic pressure would force the belligerents to negotiate with the United States. The Nonimportation Act of 1806 was followed by the Embargo Act of 1807. Difficulty of enforcement and economic conditions that rendered England and the Continent more or less independent of America made the embargo ineffective, and in 1809 it gave way to a Nonintercourse Act. This in turn was superseded by Macon's Bill No. 2, which repealed the trade restrictions against Britain and France with the proviso that if one country withdrew its offensive decrees or orders, nonintercourse would be reimposed with the other.

In 1809, after the passage of the Nonintercourse Act, a satisfactory agreement had been reached with the British minister in Washington, David Erskine, who promised repeal of the orders in council. The pact was disavowed by Foreign Secretary George Canning, however, and Erskine was replaced by F. J. Jackson, who soon proved himself persona non grata to the U.S. government. Subsequently, by a dubious commitment, Napoleon tricked James Madison, who had succeeded Jefferson as President, into reimposing (1811) nonintercourse on England. Negotiations with Britain for repeal of the orders in council continued without result; just before the declaration of war, yet too late to prevent it, the orders in council were repealed.

In reality, it was not so much the infringement of neutral rights that occasioned the actual outbreak of hostilities as the desire of the frontiersmen for free land, which could only be obtained at the expense of the Native Americans and the British. Moreover, the West suspected the British, with some justification, of attempting to prevent American expansion and of encouraging and arming the Native Americans. Matters came to a head after the battle of Tippecanoe (1811); the radical Western group believed that the British had supported the Native American confederacy, and they dreamed of expelling the British from Canada. Their militancy was supported by Southerners who wished to obtain West Florida from the Spanish (allies of Great Britain). Among the prominent ?war hawks? in the 12th Congress were Henry Clay, John C. Calhoun, Langdon Cheves, Felix Grundy, Peter Porter, and others, who managed to override the opposition of John Randolph and of the moderates.

Course of the War
War was declared June 18, 1812. It was not until hostilities had begun that Madison discovered how woefully inadequate American preparations for war were. The rash hopes of the ?war hawks,? who expected to take Canada at a blow, were soon dashed. The American force under Gen. William Hull, far from gaining glory, disgracefully surrendered (Aug., 1812) at Detroit to a smaller Canadian force under Isaac Brock. On the Niagara River, an American expedition was repulsed after a successful attack on Queenston Heights, because the militia under Stephen Van Rensselaer would not cross the New York state boundary.

On the sea, however, the tiny American navy initially gave a good account of itself. The victory of the Constitution, under Isaac Hull, over the Guerri?re and the capture of the Macedonian by the United States (Stephen Decatur commanding) were two outstanding achievements of 1812. The smaller vessels also did well, and American privateers carried the war to the very shores of England. In 1813 the British reasserted their supremacy on the sea; the Chesapeake, under Capt. James Lawrence (?Don't give up the ship!?), accepted a challenge from the Shannon and met with speedy defeat. Most of the American ships were either captured or bottled up in harbor for the duration of the war.

It was on inland waters, however, that the American navy achieved its most notable triumphs?victories that had an important bearing on the course of the war. In Jan., 1813, at the Raisin River, S of Detroit, American troops suffered another defeat. But with the victory of Capt. Oliver Perry on Lake Erie in Sept., 1813, American forces, under Gen. William Henry Harrison, were able to advance against the British, who burned Detroit and retreated into Canada. Harrison pursued and defeated them in a battle at the Thames River (see Thames, battle of the), in which Tecumseh, the Native American chief, was killed. Yet the feeble efforts of James Wilkinson along the St. Lawrence River did nothing to improve the situation on the New York border.

The first months of 1814 held gloomy prospects for the Americans. The finances of the government had been somewhat restored in 1813, but there was no guarantee of future supplies. New England, never sympathetic with the war, now became openly hostile, and the question of secession was taken up by the Hartford Convention. Moreover, with Napoleon checked in Europe, Britain could devote more time and effort to the war in America.

In July, 1814, the American forces along the Niagara River, now under Gen. Jacob Brown, maintained their own in engagements at Chippawa and Lundy's Lane. Shortly afterward, Sir George Prevost led a large army into New York down the west side of Lake Champlain and seriously threatened the Hudson valley. But when his accompanying fleet was defeated near Plattsburgh (Sept., 1814) by Capt. Thomas Macdonough, he was forced to retreat to Canada. In August, a British expedition to Chesapeake Bay won an easy victory at Bladensburg and took Washington, burning the Capitol and the White House. The victorious British, however, were halted at Fort McHenry before Baltimore.

Negotiations for Peace
The Fort McHenry setback and the American victory at Plattsburgh helped to persuade British statesmen to agree to end the war, in which no decisive gains had been made by either side. For some time negotiations for peace had been taking place. Although Great Britain had refused an early Russian offer to mediate between it and the United States, the British entered into direct peace negotiations at Ghent in mid-1814. The American delegation to the meeting at Ghent was headed by John Quincy Adams, Henry Clay, and Albert Gallatin. After long and tortuous discussions, a treaty (see Ghent, Treaty of) was signed (Dec. 24, 1814), providing for the cessation of hostilities, the restoration of conquered territories, and the setting up of boundary commissions.

The final action of the war took place after the signing of the treaty, when Andrew Jackson decisively defeated the British at New Orleans on Jan. 8, 1815. This victory, although it came after the technical end of the war, was important in restoring American confidence. Although the peace treaty failed to deal with the matters of neutral rights and impressment that were the ostensible cause of the conflict, the war did quicken the growth of American nationalism. In addition, the defeats suffered by the Native Americans in the Northwest and in the South forced them to sign treaties with the U.S. government and opened their lands for American expansion.