That's a bit more complicated don't you think? 70+ years with America as a superpower (20+ where it is almost the only one in its class) makes it easy to forget that things could have been massively different. Imagine a case where the Soviet Union did not dissolve, but stabilized as a military and economic equal to the US. Would you say that Canada's peace and prosperity would be guaranteed in this alternative universe? What about other countries in eastern Europe or the Middle East?

To give you an couple examples in the current real world, imagine if South Korea or Taiwan didn't have such good relations with America in the post-WW2 peace. It is not that far fetched to think that there could be a single communist Korea, Taiwan could have been swallowed up by mainland China.