Relations between Canada and the United States have historically been extensive, given the two countries' shared origins and border, which is the longest in the world. Starting with the American Revolution, when Loyalists were resettled in Canada, a vocal element in Canada has warned against American dominance or annexation. The War of 1812 saw invasions across the border in both directions, but the war ended with unchanged borders. The border was demilitarized, as was the Great Lakes region. The British ceased aiding Native American attacks on the United States, and the United States never again attempted to invade Canada. Apart from minor unsuccessful raids, it has remained peaceful.
As Britain decided to disengage, fears of an American takeover played a role in the Canadian Confederation (1867), and Canada's rejection of free trade (1911). Military collaboration was close during World War II and continued throughout the Cold War, bilaterally through NORAD and multilaterally thro