When Britain entered into conflict before the Treaty of Westminster in 1931, which eventually made Canada self-governing, Canada was expected to join as well. However, for the United States and Canada the relationship has always been one with clear boundaries. One major difference is Canada's willingness to help the United States in the conflict. Instead of the days when Canada had to trudge across the world to South Africa and fight in the Boer War for Britain, it now uses certain criteria. Canada fought in the Korean War with the United States, but did not fight with the United States in Vietnam. The same story can be seen in Afghanistan, when Canada sided with the United States, but in the Iraq war it did not. Canada now appears to maintain the logic that if there is a multilateral, NATO- or UN-approved operation, it will leave. The same example can be seen in the NATO bombing of Yugoslavia in the 1990s, in which Canada participated. In both the Vietnam and Iraq wars there were no sanctions, just as there were no sanctions in Canada