a super power is based on economic, political, cultural and military power.
The United States has all of those. US economy tanks, everyone's does. Politically is obvious. A presidential visit basically shuts down entire cities, regardless of where he goes. (more true of obama than most other presidents)
Cultural power is interesting because a lot of it comes down to widespread advertising. Take for example Coca Cola, an American company. You can go to the most obscure village in Africa, and odds are there will be someone who knows about coca cola.
Military is simple. The US isn't the biggest, but easily one of, if not the most effective military powers. If a country is doing questionable things the US can do something as easy as having an aircraft carrier sit off their coast, and they will stop. The US can also deploy troops just about anywhere in the world in a matter of hours.
Not knocking canada here, but saying the US isn't a superpower is simply not true.