So, here's my defense plan for Canada. Basic philosophy: it is unsafe to wait for an attack.
1. Get public confirmation from NATO that Article 5 applies even if the aggressor is also a NATO member.
2. Send an ultimatum to Washington demanding a public acknowledgement of Canadian sovereignty by the President and confirmation of non-aggression.
3. In the absence of that acknowledgement, sever diplomatic ties, close the borders, and embargo trade. Blow bridges, tear up roads and rail lines.
Start by Putting up a chainlink and barbed wire fence at the border with a second steel wire and steel post barrier 50 meters back as a buffer, might sound harsh but it will be necessary at some point.
@oscarfalcon does that really help with tanks?
It does not but it gets a very special message across to the would-be oppressors: "don't fuck with us", this is protected land...
@oscarfalcon Good point!