It's a wonderful question, and it enables me to raise the point that some ships actually travel submerged and the issue of submarine transits of the Northwest Passage is a very pertinent issue, particularly because the Los Angeles Times last Saturday reported that a U.S. nuclear-powered submarine from Norfolk, Virginia, is going to be participating in an exercise north of Prudhoe Bay, Alaska, in the next couple of weeks.
So one of the questions your committee should ask is whether or not Canada and the United States have a cooperation agreement that extends to submarine transits of the Northwest Passage, because as the Arctic becomes busier, we will become more and more aware of these, if in fact they do occur.
But in terms of the actual frozen character of the water, at least during part of the year, this does enable Canada to say to the United States, look, the Northwest Passage is different from other potential international straits elsewhere in the world, and therefore you do not need to be so concerned about a precedent; you could recognize Canadian sovereignty over the Northwest Passage and not worry about it creating a precedent for the Strait of Malacca or the Strait of Gibraltar, because those straits are not covered with ice in the winter.