<P> However, according to the U.S Army Center of Military History, the "land - hungry frontiersmen", with "no doubt that their troubles with the Native Americans were the result of British intrigue", exacerbated the problem by "(circulating stories) after every Native American raid of British Army muskets and equipment being found on the field". Thus, "the westerners were convinced that their problems could best be solved by forcing the British out of Canada". </P> <P> The British had the long - standing goal of creating a large, "neutral" Native American 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 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 . Although much of the area remained under British or British - allied Native Americans' control until the end of the war, the British, at American insistence and with higher priorities, dropped the demands . </P> <P> American expansion into the Northwest Territory was being obstructed by various Indian tribes since the end of the Revolution, who were supplied and encouraged by the British . Americans on the western frontier demanded that interference be stopped . There is dispute, however, over whether or not the American desire to annex Canada brought on the war . Several historians believe that the capture of Canada was intended only as a means to secure a bargaining chip, which would then be used to force Britain to back down on the maritime issues . 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, many historians believe that a desire to annex Canada was a cause of the war . This view was more prevalent before 1940, but remains widely held today . 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 ." </P> <P> Madison believed that British economic policies designed to foster imperial preference were harming the American economy and that as British North America existed, here was a conduit for American strugglers who were undercutting his 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 North American goods to Europe at the expense of the U.S. economy, and if the United States controlled the resources of British North America like 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 . Many Americans believed it was only natural that their country should swallow up North America with one Congressman, John Harper saying 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 (modern 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 then believed that many men in Upper Canada would rise up and greet an American invading army as liberators . That did not happen . One reason 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 former President 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 ." </P>

What was the rationale behind the american invasion of canada
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