Bush is maintaining the US's traditional position that the Northwest passage -- should it open up as a result of all those Middle American SUVs -- is an international passageway, and therefore not under Canada's sovereignty. The Financial Times notes that former ambassador Paul Celluci is advocating a change in the American position.
You have to wonder what we get out of taking a disproportionate share of the allied burden in Afghanistan. We pay in blood and money, and in increased risk of attack at home. We get passports at the border, the softwood lumber "deal", and an unwillingness to back us on the Arctic.
It is in everyone's interest when a responsible country takes jurisdiction over a waterway. If the Northwest Passage is ours, then our laws apply. We can do something about polluters and terrorists.* Bush is weakening Harper at a time when the Afghan mission is in real doubt.
*Come on, commenters. The jokes write themselves.