Britain's entry into the war had almost eliminated Germany's chances of persuading the South American governments to support a pro-Nazi policy. In view of all the changes, Washington adjusted its strategy to three main objectives: the continental defense of the United States; the joint defense of Canada; and the Pan-American defense of the Western Hemisphere. These three objectives are worth looking at individually. The first system, aimed at defending the "continent," was a straightforward scheme devised by the army and the army air force for defending US national territory. The second system, affecting "North America," that is a joint defense operation with Canada was more political than strategic, as the linking of two defense systems against possible external threat raised diplomatic and legal snags because of the official neutral position of the United States—Canada had been at war with Germany since 1939. The third system of defense focused on the Western Hemisphere as a whole.