There are few issues in the US I see motivating such an extreme reaction within a state border for the majority of US states. The only breaking points I see ar

There are few issues in the US I see motivating such an extreme reaction within a state border for the majority of US states. The only breaking points I see are reasonably well handled through a legal decoupling of states and the federal government. The big item issues such as - Federal bans on abortion - Controversial Presidential elections - A series of unfortunate Supreme court decisions - Immigration - Infrastructure spending Are all issues which can be handled with a legal decoupling. If all sides remained notionally in Congress, then there is very little likelihood that Congress would address the matter. A sensible supreme court would leave it as a political issue for a few decades before declaring a defacto status as was done for West Virginia's statehood. For all intents and purposes, a de facto decoupling would look more like a return to State relationships prior to 1900 then a secession. While some may wish for a military based solution to stop a legal decoupling... there simply does not seem to be a plausible route for any military solution by any party. Russia made it ~100km into Ukraine before being stopped, it's 2900 KM between Houston and Boston - all means of ending such a stalemate would escalate to MAD as the military remains spread across states for political and defense purposes. Even in the civil war, the North was unable to enforce integration of the south through reconstruction.