[kyboren]

I wouldn't consider it a threatening act. But I am not Commander in Chief of the US Armed Forces.

I am not advocating an invasion of Canada. I deplore the annexation rhetoric coming from POTUS. I don't believe there is a serious intention to annex Canada through military force, but I do believe loose talk like what we've seen harms our national security interests and understandably frightens our utterly vulnerable neighbors.

However, I also believe that in this new Great Game it's important to understand the actual state of the board and the likely actions/reactions of the other players.

Deluding oneself that Canada can resist a full-scale invasion by their only neighbor with overwhelming military, economic, industrial, financial, and diplomatic advantages because foreign nations will be obliged to join the war on Canada's side is unwise.

Deluding oneself that developing nuclear weapons would not be an easy casus belli for an actually hostile US is similarly unwise.

[sirtaj]

You're right, it's seeking and developing nuclear weapons that has been the problem historically. Once you have them it's fine, the sabre-rattling pretty much stops. Worked for India, Pakistan, China, North Korea.

[kelipso]

If it’s Canada, even already having nuclear weapons would be unacceptable to US security. See Cuban missile crisis.