In case anyone has forgotten, Canada refused to participate in the first generation ("Star Wars") defense of North America because it knew that the US would protect it anyway. Now the US wants to establish a second generation missile defense shield ("Iron Dome") over the continent. This will require additional Arctic anti-missile bases to the east of Alaska. If Canada again refuses to participate in its own defense, the US will have to look to Greenland. If Greenland also refuses, should the US just forget about its own national security?