Thread closed. Defence Talk is an international defence forum, to discuss defence matters. It is not a place to discuss conspiracy theories, politics, or improbable pet rock scenarios that ignore a host of issues.
For this specific scenario, it would require two US states and a Canadian province to secede from their respective parent nations, and then join to form a fourth nation in North America. All this would need to occur prior to the start of the desired scenario
At present, just like in 1860, there is no legal mechanism in the US for a state to secede. There are legal mechanisms in place which could be used to create a legal mechanism for a state to leave the Union. However, there would need to be very compelling political reasons for a state to serious consider seceding, and for the US Constitution to be amended to provide a path for secession. There would need to be even more compelling reasons for a state to consider unilaterally seceding and risking a civil war with the rest of the US. And all of the sociopolitical discussions why a state or states might wish to leave the Union are Off Topic for discussion on a defence forum.
Again, Defence Talk if an international defence forum, for the discussion of 'real' defence issues. If you wish to participate, please stay and do so. However, if discussion of 'real' defence matters is not what interests you, I suggest finding a forum that caters to your desired topic of discussion.