It would be cool if the Western provinces seceded to the United States. We would have a land link between the lower 48 and Alaska (a good thing strategically) and, if I'm correct, we would get a handful more conservative U.S. Senators.
What would be the eastern boundary? The Alberta-Saskatchewan border, the Saskatchewan-Manitoba border, the Manitoba-Ontario border, Lake Superior area or the Ontario-Quebec border with a ring around the GTA?