Thompson therefore endeavoured to arouse the leading statesmen of the Mother Country to the significance of American policy as he saw it. The leading men of the United States, he pointed out, all held it as a maxim that no foreign power had any right to any part of North America; and that every means ought to be employed to expel this foreign power. They were well aware of the insecurity of their position. On their northern frontier a powerful foreign nation was in possession for upwards of one thousand miles. Their sea coast was open and exposed. The numerous slaves in their southern and western states were ready for revolt; while to the west were seventy thousand Indian warriors, who had been compelled by force or fraud to quit their lands, and who could readily be aroused to a war of revenge. Accordingly, he alleged, the Americans had aimed ever since the treaty of 1783 to restrict as far as possible the territory of Great Britain and to destroy her influence over the Indians. Their method was to advance claims which, though exorbitant, would be softened and rendered familiar by the operation of time, and in each case, when the settlements came to be made, they aimed to be in possession of the areas in dispute. British subjects on the other hand had been compelled to yield ground from point to point, because they could not rely on the support of the Imperial government if they stood firm. As he wrote, the situation was acute along the whole length of the frontier. On the Quebec border, all the way from St. Regis on the St. Lawrence to the Connecticut river, the Americans were holding fast to a line some distance north of the true parallel of 45° which had been named as the frontier in the original treaty of peace and confirmed some years later by the award of the King of the Netherlands. In the St. Mary's river, American commissioners were claiming two of the three boat channels and all but two or three hundred yards of a river bed four miles wide. If their demands at that point were granted, Great Britain would surrender the keys to her northern and western dominions, and shut herself off from communication with them except by the frozen shores of the Hudson Bay. At the head of Lake Superior, the Americans had driven the British traders from two of the three possible routes joining the Great Lakes with the Lake of the Woods, and were claiming that the treaty of 1783 implied a boundary running along the line of the third and last possible route (the Kaministiquia river), although the very existence of that route was utterly unknown until at least seventeen years after the treaty was drawn. In the present congress they were again urging the necessity of taking possession of what they called the "Oregon Territory," and demanding a line down the middle of the Columbia river to the Pacific ocean.