I think it's a piece of North America that we are not fully participant in. From the standpoint of our own sovereignty and security, it would be preferable to be integrated because I don't see a reason why not to be. It's a question of attitude and altitude. For some reason we're willing to participate in the air-breathing protection, but not in protection from a weapon which, because of its trajectory, exits the atmosphere. We're willing to support a ballistic missile defence for allies in Europe, but not participate fully in our own defence.
The other thing to remember about BMD is that the North American part is the terminal part. The United States has forward-based Aegis cruisers, particularly around the Korean Peninsula, and would hope to intercept the missile early on. Again, from the American standpoint, Canada's unease over this is not something that either puts America at risk or gets in the way of the United States handling the problem.