Actually it's pretty hard to pick the US' greatest gift to Canada that isn't also a gift to the rest of the world. I can't think of much that's unique and specific to Canada. Continental security perhaps? We were able to let our military languish and decline for decades because the Americans filled the gap and successive federal administrations, both Liberal and Conservative, knew they would. The current Conservative administration is the first one since 1945 that's shown any serious interest in supporting and expanding our military forces, though I know there are some here who wouldn't view that as positive. Machjo's also right that the US contributed to our very presence. The War of 1812 comes to mind; it helped generate a distinct sense of Canadianness separate from the British identity, never mind that it was based mostly on mythology. That's where all national identities come from. The transcontinental railway was built in the 1870s partly as a response to American expansionism, so I suppose we could be grateful for that too. That was also a factor in the creation of the RCMP. But those all seem a bit negative to me. I really don't think the US has given Canada any significant gifts that it hasn't also given to the world, and that list is endless. Greatest among them, in my considered opinion, is the US Declaration of Independence and the US Constitution. Those are great documents from some of the world's best minds, they embody the best of Enlightenment values, and they show what is possible when you trust the best of human reason to find solutions to human problems.
