The U.S. administration, particularly the current one, can have a much bigger impact on the lives of all of us than the effect of our own government. The "war on terror", global recessions etc. etc. are just some examples. Whether or not the Liberals will take more money from us than the Conservatives, or who will provide us with better access to affordable health care are certainly issues which are of concern to us, but not to the same degree.
We are a global family with a global economy, and the U.S. has a much larger role to play in how the system works. Besides, with all the hoopla, U.S. elections are much more fun!