The War of 1812 began on June 18, 1812. There were several reasons that led to hostilities between the United States and Great Britain. At the time, Great Britain was involved in a conflict in Europe, fighting the French under Napoleon. United States merchant vessels claimed neutrality. The British, however, searching for deserting sailors, began impressing and seizing United States sailors. Award-winning historian Alan Taylor argues that the British saw the United States seamen as mutinous citizens. Using this justification allowed the British admiralty to forcibly conscript manpower to fight Napoleon. News of these events, along with the economic damage and loss of United States prestige they entailed, contributed to the declaration of war on June 18.
While impressment was a major reason for war, the perception of hostile British intentions in Canada also led to military action. Many in the United States felt that the British were using Canada as a base to support Indian raids in the western United States. By forcing the British out of Canada, the United States would enable safe expansion westward. New territory would grant more citizens access to additional land and economic resources. Hostility towards the Indians and sensitivity to any perceived infringement on American independence led to an invasion of Canada as soon as war was declared.
British society at the time also debated a potential conflict with their former colonies. The British admiralty argued that impressment was a lenient policy. Believing most sailors on American ships were rightly British and therefore committed treason by escaping British naval duty or serving another country, the Admiralty noted that a legal alternative would be death by hanging. British policy worked similarly in Canada, where settlers from the United States were forcibly recruited into the British army, again under the context that they were mutinous British subjects. Meanwhile, runaway slaves from the United States were given refuge and freedom in Canada. The British hoped that these various methods, along with a convincing military victory, would lead portions of the United States to rejoin their empire. Yet the British were not entirely composed of war hawks, and American threats did not go unnoticed. On June 16, 1812, heeding calls by the American ambassadors, the British rescinded the policy of impressment. The United States, not having access to the news (mail at the time took four weeks to travel between the two countries), declared war on June 18. Fighting commenced with the American invasion of Canada weeks later.
The invasion of Canada by the United States did not immediately trigger a response from Great Britain. The British, involved in a war with Napoleon, did not immediately take notice of the American aggression. Most Canadians remained loyal to the British Empire, and they successfully defended their territory without significant support from the mother country. It was only after Canadian threats and pleas by the Governor-General of Canada (and after victory in Spain turned the tide against Napoleon in Europe), James Henry Craig that the British responded with an invasion of Maryland. The invasion of Maryland was meant to distract and occupy American resources that had been involved in the invasion of Canada.
British hopes for re-absorbing America into their empire were bolstered by the Hartford Convention. After two years which saw the Americans repulsed from Canada and their new capital of Washington captured by the British forces that invaded Maryland, prominent Northeastern merchants and powerful politicians met in Hartford in 1814 to discuss seceding from the United States and rejoining the British empire. The convention was called not just in response to military defeat, but in reaction to economic policies put in place by the Democratic-Republican government that were perceived as harmful to merchants, the primary profession of the attendees of the convention. Ultimately, the idea of secession was rejected and New England remained within the United States, but New Englanders remained lukewarm in their support of the war, especially the western front that did not impact their commercial shipping.
Taylor, Alan. The Civil War of 1812: American Citizens, British Subjects, Irish Rebels, & Indian Allies. New York: Alfred A. Knopf, 2010. Print.