A Canadian asked and Will Wilkinson responded with the most obvious follow up question: Why not Mexico, too?
Such a merger makes perfect sense. No two countries on Earth are as socially and economically integrated as the U.S. and Canada. They share geography, values and a gigantic border. Their populations study, travel and do business together and intermarry in great numbers. If they were corporations (or European states), they would have merged a long time ago. And each has what the other needs: The U.S. has capital, manpower, technology and the world's strongest military; Canada has vast reserves of undeveloped resources.
Canadians have traditionally bristled at the thought of falling under the sway of the U.S., but without a deeper cross-border partnership, we face some grim existential challenges. With its small, aging population and relatively small economy, Canada lacks the resources to develop and defend its gigantic piece of real estate. Through a series of aggressive buyout attempts and transactions, China has targeted Canada's resources and empty landmass. In 2007, Russia used a small submarine to symbolically plant its flag on the ocean floor beneath the North Pole and underscore its claim to a large swath of the resource-rich Arctic, and Russian President Vladimir Putin has been pushing the U.N. to affirm his claims to the region.