In June 1812 the United States declared war on Great Britain and promptly invaded Upper Canada. The root of this war lay as much in the American-Indian conflict along the northwestern frontier as in American-British maritime rivalry in the previous decade. After three years of fighting British, Canadian, and Indian forces, the United States had lost territory along its east coast, in the west, and on the Pacific coast. Even the few American military and naval successes could not begin to outweigh the economic stranglehold of the British blockade. The weight of British sea power determined the outcome of the war, with the United States unable to achieve its war aims. Negotiations begun by President James Madison in 1812 ultimately concluded in 1814 with the restoration of the pre-war situation. In surviving the military might of the United States Canadians discovered the essentials of nationhood.
Lacking a navy, American strategy was based on a quick land war to be concluded before British reinforcements could cross the Atlantic. The Americans also expected that Canadians would not fight. The British, exhausted by their wars with Napoleon, relied entirely on defensive measures and a naval blockade. In order of priority the American objectives were Quebec, Montreal, Kingston, and Niagara. Quebec had never been taken without naval support, but Montreal was vulnerable through the well trodden Champlain corridor. The Americans, lacking effective military leadership and hampered by reluctant New Englanders, failed to take Montreal, and simply wasted their strength in uncoordinated thrusts on the Canadian perimeter.
Military logistics determined victory or defeat as much as army manoeuvres and individual bravery did. The Americans had the advantage of internal (protected) transport and communications, versus the Britons' long transatlantic crossing. British soldiers, supplies, and equipment, necessarily funnelled up the St Lawrence, were vulnerable to attack, especially between Montreal and Kingston. Throughout the war troops, munitions, and provisions were transported by water routes. In rain or thaw, roads became quagmires; winter travel over icy surfaces was easier. Meagre farm output in Canada made the United States the main source of food, fodder, and military stores for the British. Three major smuggling routes were used: across the St Lawrence at Prescott, the back trails of the Champlain corridor, and by sea to Nova Scotia from New England.