and Great Britain severed their last formal constitutional links in March 1982. Ottawa has taken steps to curb U.S. economic and cultural "imperialism." Quebec separatists have edged closer to secession. Oil-rich Alberta is resisting Ottawa's move to tighten up the world's loosest federal system. Considering everything above the 49th parallel to be like everything below it, most Americans pay little attention to their neighbor "upstairs." Yet Canada is a very different place,...