The War of 1812 was a conflict fought between the United States and the United Kingdom, with their respective allies, from June 1812 to February 1815. Historians in Britain often see it as a minor theatre of the Napoleonic Wars; historians in the United States and Canada see it as a war in its own right.
From the outbreak of war with Napoleonic France, Britain had enforced a naval blockade to choke off neutral trade to France, which the US contested as illegal under international law. To man the blockade, Britain pressed American merchant sailors into the Royal Navy. American sentiment grew increasingly hostile toward Britain due to incidents such as the Chesapeake–Leopard affair, which happened five years before the war. The British were in turn outraged by the Little Belt affair in 1811, in which 11 British sailors died. Britain supplied arms to American Indians who raided American settlers on the frontier, hindering American expansion and provoking resentment. Historians debate whether the desire to annex some or all of British North America (Canada) contributed to the American decision to go to war. However, the Western interest was in expansion into American territories such as Indiana, Illinois, Michigan, and Wisconsin, where they were threatened by Indians supported by the British. On June 18, 1812, President James Madison signed into law the American declaration of war, after heavy pressure from the War Hawks in Congress.
With most of its army in Europe fighting Napoleon, Britain adopted a defensive strategy, with offensive operations initially limited to the border and the western frontier. American prosecution of the war effort suffered from its unpopularity, especially in New England, where it was referred to as "Mr. Madison's War". American defeats at the Siege of Detroit and the Battle of Queenston Heights thwarted attempts to seize Upper Canada, improving British morale. American attempts also failed to invade Lower Canada and capture Montreal. In 1813, the Americans won the Battle of Lake Erie, gaining control of the lake, and they defeated Tecumseh's Confederacy at the Battle of the Thames, securing a primary war goal. The Americans made a final attempt to invade Canada but fought to a draw at the Battle of Lundy's Lane during the summer of 1814. At sea, the powerful Royal Navy blockaded American ports, cutting off trade and allowing the British to raid the coast at will. In 1814, one of these raids burned the capital, but the Americans later repulsed British attempts to invade New York and Maryland, ending invasions from Canada into the northern and mid-Atlantic states. In early 1815, the Americans decisively defeated the invading British Army attacking New Orleans, Louisiana. Fighting also took place in Spanish Florida; a two-day battle for the city of Pensacola ended in Spanish surrender.
In Britain, there was mounting opposition to wartime taxation, and merchants demanded to reopen trade with America. With the abdication of Napoleon, Britain's war ended with France and Britain ceased impressment, rendering the issue irrelevant of the impressment of American sailors. The British were then able to increase the strength of the blockade on the United States coast, smothering American maritime trade, but their attempts failed to invade America, at which point both sides began to desire peace.
Peace negotiations began in August 1814, and the Treaty of Ghent was signed on December 24, 1814. News of the peace did not reach America for some time. In February 1815, news reached the East Coast concerning the great victory at New Orleans—at the same time as news of the Christmas peace treaty. The Americans triumphantly celebrated the restoration of their national honour, leading to the collapse of anti-war sentiment and the beginning of the Era of Good Feelings, a period of national unity. The treaty was unanimously ratified by the US Senate on February 17, 1815, ending the war with no boundary changes.
Historians have long debated the relative weight of the multiple reasons underlying the origin of the War of 1812. This section summarizes several contributing factors which resulted in the declaration of war by the United States.
Honour and the second war of independence
As Risjord (1961) notes, a powerful motivation for the Americans was the desire to uphold national honour in the face of what they considered to be British insults, such as the Chesapeake–Leopard affair.H. W. Brands writes: "The other war hawks spoke of the struggle with Britain as a second war of independence; [Andrew] Jackson, who still bore scars from the first war of independence, held that view with special conviction. The approaching conflict was about violations of American rights, but it was also about vindication of American identity." Americans at the time and historians since have often called it the United States' "Second War of Independence".
The British, at the same time, were offended by what they considered insults, such as the "Little Belt" affair. This gave them a particular interest in capturing the United States flagship President, which they succeeded in doing in 1815.
Impressment and naval actions
In 1807, Britain introduced a series of trade restrictions via the Orders in Council to impede neutral trade with France, whom Britain was fighting in the Napoleonic Wars. The United States contested these restrictions as illegal under international law. Historian Reginald Horsman states that "a large section of influential British opinion, both in the government and in the country, thought that America presented a threat to British maritime supremacy." The American merchant marine had nearly doubled between 1802 and 1810, making it by far the largest neutral fleet. Britain was the largest trading partner, receiving 80 percent of American cotton and 50 percent of other American exports, and the British public and press were resentful of the growing mercantile and commercial competition. The United States' view was that Britain's restrictions violated its right to trade with others.
During the Napoleonic Wars, the Royal Navy expanded to 176 ships of the line and 600 ships overall, requiring 140,000 sailors to man them. The Royal Navy could man its ships with volunteers in peacetime, but it competed in wartime with merchant shipping and privateers for a small pool of experienced sailors, so it turned to impressment from ashore and from foreign and domestic shipping when it could not operate its ships with volunteers alone.
The United States believed that British deserters had a right to become American citizens, but Britain did not recognize a right whereby a British subject could relinquish his citizenship and become a citizen of another country. The British Navy, therefore, considered any American citizen liable for impressment if he was born British. Aggravating the situation was the United States' reluctance to issue formal naturalization papers, and the widespread use of unofficial or forged identity or protection papers among sailors. This made it difficult for the Royal Navy to distinguish Americans from non-Americans and led it to impress some Americans who had never been British. Some gained freedom on appeal. The Admiralty estimated that there were 11,000 naturalized sailors on United States ships in 1805, and US Secretary of the Treasury Albert Gallatin stated that 9,000 US sailors had been born in Great Britain or Ireland. Captain Isaac Chauncey found in 1808 that 58-percent of sailors based in New York City were either naturalized citizens or recent immigrants. Of these 150 naturalized sailors, 80 were from Ireland and 54 from other parts of the United Kingdom.
American anger grew when British frigates were stationed just outside US harbours and in view of US shores to search ships and impress men while within US territorial waters. Well-publicized impressment actions outraged the American public, such as the Leander affair and the Chesapeake–Leopard affair.
The British public were outraged in their turn by the Little Belt affair, in which a large American ship clashed with a small British sloop, resulting in the deaths of 11 British sailors. Both sides claimed that the other fired first, but the British public in particular blamed the US for attacking a smaller vessel, with calls in some newspapers for revenge, while the US was encouraged by the fact that they had won a victory over the Royal Navy. The US Navy also forcibly recruited British sailors, but the British government saw impressment as commonly accepted practice and preferred to rescue British sailors from American impressment on a case-by-case basis.
The Northwest Territory consisted of Ohio, Indiana, Illinois, Michigan, and Wisconsin, and was the battleground for conflict between the United States and various Indian tribes. The British Empire had ceded the area to the United States in the Treaty of Paris in 1783, both sides ignoring the fact that the land was partly inhabited by various tribes, including the Miami, Winnebago, Shawnee, Fox, Sauk, Kickapoo, Delaware, and Wyandot. Some warriors had left their tribes to follow Tenskwatawa, the Shawnee prophet and the brother of Tecumseh. Tenskwatawa had a vision of purifying his society by expelling the "children of the Evil Spirit", by which he meant the American settlers. The Indians wanted to create their own state in the Northwest to end the American threat forever, as it became clear that the Americans wanted all of the land in the Old Northwest for national growth. Tenskwatawa and Tecumseh formed a confederation of numerous tribes to block American expansion. The British saw the Indian tribes as valuable allies and a buffer to their Canadian colonies, so they began to provide arms and ammunition to the Indians; the subsequent Indian attacks on American settlers in the Northwest further aggravated tensions between Britain and the United States. Raiding grew more common in 1810 and 1811; westerners in Congress found the raids intolerable and wanted them permanently ended. British policy was divided towards the Indians. On the one hand, the British wanted to encourage Indian raids in order to keep the Americans fighting in the Northwest; they also wanted to preserve a region which provided rich profits for Canadian fur traders. On the other hand, they feared that too much support for the Indians would cause a war with the United States. Tecumseh's plans for an Indian state in the Northwest would benefit British North America by making it more defensible, but the defeats suffered by Tecumseh's confederation made the British leery of going too far to support what was probably a losing cause. British diplomats attempted to defuse tensions on the frontier in the months preceding the war.
Americans believed that British officers paid their Indian allies to scalp American soldiers, c. 1812
The confederation's raids hindered American expansion into rich farmlands in the Northwest Territory. Pratt writes:
There is ample proof that the British authorities did all in their power to hold or win the allegiance of the Indians of the Northwest with the expectation of using them as allies in the event of war. Indian allegiance could be held only by gifts, and to an Indian no gift was as acceptable as a lethal weapon. Guns and ammunition, tomahawks and scalping knives were dealt out with some liberality by British agents.
However, the frontiersmen, according to the U.S. Army Center of Military History, had no doubt that their troubles with the Indians "were the result of British intrigue", and many settlers began circulating stories of British Army muskets and equipment being found on the field after Indian raids. Thus, "the westerners were convinced that their problems could best be solved by forcing the British out of Canada". 
The British had the longstanding goal of creating a large Indian state to cover much of Ohio, Indiana, and Michigan. They made the demand as late as the fall of 1814 at the peace conference, but they lost control of western Ontario in 1813 at key battles on and around Lake Erie. These battles destroyed the Indian confederacy which had been the main ally of the British in that region, weakening its negotiating position. Much of the area remained under British or British-allied Indian control until the end of the war, but the British dropped the demands.
A map of the Canadas from 1812. It has been disputed whether or not the American desire to annex Canada brought on the war.
American expansion into the Northwest Territory had been obstructed by various Indian tribes since the end of the Revolution——tribes who were supplied and encouraged by the British—and Americans on the western frontier demanded that the British cease their interference. In June 1812, secretary of state James Monroe said, "It might be necessary to invade Canada, not as an object of the war but as a means to bring it to a satisfactory conclusion." Speaker Henry Clay repeated the same argument. Canada was the only British possession that the Americans could easily attack, and capturing it would secure a bargaining chip which could then be used to force Britain to back down on the maritime issues. As New Zealand historian J.C.A. Stagg observes, it would also cut off food supplies for Britain's West Indian colonies, and temporarily prevent the British from continuing to arm the Indians. However, some historians believe that a desire to annex Canada was a cause of the war. Congressman Richard Mentor Johnson told Congress that the constant Indian atrocities along the Wabash River in Indiana were enabled by supplies from Canada and were proof that "the war has already commenced." "I shall never die contented until I see England's expulsion from North America and her territories incorporated into the United States."
Loyalists landing in New Brunswick. Loyalists settlers to the Canadas were Revolution-era exiles, hostile to union with the U.S., whereas newer immigrants to the Canadas were neutral or supportive of the British.
Madison believed that British economic policies were harming the American economy because they were designed to bolster British trade; he also felt that Canada was a conduit for American smugglers who were undercutting his own trade policies, which thus required that the United States annex British North America. Furthermore, Madison believed that the Great Lakes-St. Lawrence trade route might become the main trade route for the export of American goods to Europe; if the United States controlled the resources of British North America such as timber, which the British needed for their navy, then Britain would be forced to change its maritime policies which had so offended American public opinion. Congressman John Harper said in a speech that "the Author of Nature Himself had marked our limits in the south, by the Gulf of Mexico and on the north, by the regions of eternal frost".
Upper Canada (southern Ontario) had been settled mostly by Revolution-era exiles from the United States (United Empire Loyalists) or postwar American immigrants. The Loyalists were hostile to union with the United States, while the immigrant settlers were generally uninterested in politics and remained neutral or supported the British during the war. The Canadian colonies were thinly populated and only lightly defended by the British Army. Americans believed that many men in Upper Canada would rise up and greet an American army as liberators. One reason that American forces retreated after one successful battle inside Canada was that they could not obtain supplies from the locals. But the Americans thought that the possibility of local support suggested an easy conquest, as Thomas Jefferson believed: "The acquisition of Canada this year, as far as the neighborhood of Quebec, will be a mere matter of marching, and will give us the experience for the attack on Halifax, the next and final expulsion of England from the American continent."
Thomas Jefferson, the third President of the United States (1801–1809), believed that the acquisition of the Canadas was a "mere matter of marching".
Some American border businessmen supported annexation because they wanted to gain control of Great Lakes trade. Carl Benn notes that the War Hawks' desire to annex the Canadas was similar to the enthusiasm for the annexation of Spanish Florida by inhabitants of the American South; both expected war to facilitate expansion into long-desired lands and end support for hostile Indian tribes (Tecumseh's Confederacy in the North and the Creek in the South). Tennessee Congressman Felix Grundy considered it essential to acquire Canada to preserve domestic political balance, arguing that annexing Canada would maintain the free state-slave state balance, which might otherwise be thrown off by the acquisition of Florida and the settlement of the southern areas of the new Louisiana Purchase.
However, historian Richard Maass argues that the expansionist theme is a myth which goes against the "relative consensus among experts that the primary U.S. objective was the repeal of British maritime restrictions". He argues that consensus among scholars is that the United States went to war "because six years of economic sanctions had failed to bring Britain to the negotiating table, and threatening the Royal Navy's Canadian supply base was their last hope." Maass agrees that expansionism might have tempted Americans on a theoretical level, but he finds that "leaders feared the domestic political consequences of doing so", particularly because such expansion "focused on sparsely populated western lands rather than the more populous eastern settlements" of Canada. Nevertheless, Maas notes that many historians continue to believe that expansionism was a cause.
Horsman argues that expansionism played a role as a secondary cause after maritime issues, noting that many historians have mistakenly rejected expansionism as a cause for the war. He notes that it was considered key to maintaining sectional balance between free and slave states thrown off by American settlement of the Louisiana Territory, and widely supported by dozens of War Hawk congressmen such as John A. Harper, Felix Grundy, Henry Clay, and Richard M. Johnson, who voted for war with expansion as a key aim.
In disagreeing with those interpretations that have simply stressed expansionism and minimized maritime causation, historians have ignored deep-seated American fears for national security, dreams of a continent completely controlled by the republican United States, and the evidence that many Americans believed that the War of 1812 would be the occasion for the United States to achieve the long-desired annexation of Canada… Thomas Jefferson well-summarized American majority opinion about the war… to say "that the cession of Canada… must be a sine qua non at a treaty of peace".
However, Horsman states that in his view "the desire for Canada did not cause the War of 1812" and that "The United States did not declare war because it wanted to obtain Canada, but the acquisition of Canada was viewed as a major collateral benefit of the conflict."
Historian Alan Taylor says that many Democratic-Republican congressmen "longed to oust the British from the continent and to annex Canada", such as Richard M. Johnson, John A. Harper, and Peter B. Porter. A few Southerners opposed this, fearing an imbalance of free and slave states if Canada was annexed, while anti-Catholicism also caused many to oppose annexing mainly Catholic Lower Canada, believing its French-speaking inhabitants unfit "for republican citizenship". Even major figures such as Henry Clay and James Monroe expected to keep at least Upper Canada in the event of an easy conquest. Notable American generals such as William Hull were led by this sentiment to issue proclamations to Canadians during the war promising republican liberation through incorporation into the United States. General Alexander Smyth similarly declared to his troops when they invaded Canada that "you will enter a country that is to become one of the United States. You will arrive among a people who are to become your fellow-citizens." A lack of clarity about American intentions undercut these appeals, however.
David and Jeanne Heidler argue that "most historians agree that the War of 1812 was not caused by expansionism but instead reflected a real concern of American patriots to defend United States' neutral rights from the overbearing tyranny of the British Navy. That is not to say that expansionist aims would not potentially result from the war." However, they also argue otherwise, saying that "acquiring Canada would satisfy America's expansionist desires", also describing it as a key goal of western expansionists who, they argue, believed that "eliminating the British presence in Canada would best accomplish" their goal of halting British support for Indian raids. They argue that the "enduring debate" is over the relative importance of expansionism as a factor, and whether "expansionism played a greater role in causing the War of 1812 than American concern about protecting neutral maritime rights."
James Madison, the fourth President of the United States (1809–1817). Madison was the leader of the Democratic-Republican Party, whose power base came from southern and western states
The U.S. was in a period of significant political conflict between the Federalist Party (based mainly in the Northeast) and the Democratic-Republican Party (with its greatest power base in the South and West). The Federalist Party favoured a strong central government and closer ties to Britain, while the Democratic-Republican Party favoured a smaller central government, preservation of states' rights (including slavery), westward expansion, and a stronger break with Britain. By 1812, the Federalist Party had weakened considerably, and the Republicans were in a strong position, with James Madison completing his first term of office and control of Congress. Support for the American cause was weak in Federalist areas of the Northeast throughout the war; fewer men volunteered to serve and the banks avoided financing the war. The negativism of the Federalists ruined the party's reputation, exemplified by the Hartford Convention of 1814–15, and it survived only in scattered areas. By 1815, there was broad support for the war from all parts of the country. This allowed the triumphant Democratic-Republicans to adopt some Federalist policies, such as the national bank which Madison re-established in 1816.