1. It doesn't matter if Canada doesn't see Russia as an enemy, the fact is Russia sees any western country as a rival, and if push came to shove, a combat opponent.
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2. Let The USA carry ALL the burden of "defending" Canada? Letting the UK carry the ball in foreign relations, is why Canada lost every territorial negotiations in the 19th century with the USA, so, uh, no letting other countries speak for you doesn't work.. The USA not letting any other country attack/occupy Canada? Uh, then why would they leave later?
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3. Canada faces no external threats? Both India, and China have declared themselves "arctic nations"...both have nuclear powered subs, which can travel under the ice...give it 30, 50 years, who knows what the world will look like..

Lets' see..China builds an "weather observation island" in the Arctic (experience showed the SC Sea  islands worked well)..There is a crisis.. USA has a choice, give up part of Alaska, or Canada, what do you think they will choose?