I wouldn’t be so sure. Copy Russia’s playbook.

Let’s say, it’s just a short special military operation to clear Vancouver of fentanyl imports from China. You don’t need the whole military on board for that. A few battalions is enough. A preceding crisis could be created that then provides a reason. The city doesn’t even need to be taken in a battle. Occupying Canada’s highway 1, railway, and blockading the port could lead to a peaceful handover of the city.

The next step is then the US needs a strategic land bridge to protect Alaska against Russia, so BC and Yukon will be temporarily under US administration.

With Mexico it’s even easier. Say cartel and drugs, special military operation, and that’s that.