Fact is we're members of NORAD, co-command actually, and last fall we signed the protocols to bring MD under the arm of NORAD, so we're already involved big time. Conceiveably, the responsibility to use the system in the face of an incoming missile could very easily fall to a Canadian, and be assured they would act according to the alliance's interest. Martin of course signed on very quietly so as not to upset his base.
There's also the possibility that there's a quid pro quo in this decision between Martin and NDP leader Jack Layton (ignorant silver spoon socialist). Martin leads a minority government and just brought down a budget. He may have made a deal to save him from a non-confidence vote. If that were to be true, and I don't put it past him to place his own political fortunes ahead of the best interests of the country, I'd want him driven from power.
Believe me, Mitch, I'm not saying the decision is sound. Given Canada's NATO membership, and given the history of militray cooperation between Canada and the United States, I'd say this decision is far from being sound.
My point is that one cannot accuse Canada of having engaged into a "deliberate act of war" because of its decision not to fund the missile shield.
As for encouraging Canada to break up, I can only say for myself that it's something we haven't done since the last 40 years ! LOL. You'll find more partisans of the break-up here, I suppose, as well as a few "invasionnists".