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.
@evan Consider taking Michigan first, and skip blowing up that nice new bridge you're building.
About half of us will welcome our new Canadian Overlords as liberators.
You will of course need to adapt to French's Ketsup and sushi pizza.