Even independent of SCOTUS, Congress would pre-empt it

Finally, states must consider how to label the exit tax and if it should be a standalone tax regime. This seemingly trivial consideration can have an enormous impact on the practical viability of the exit tax, particularly given the pejorative nature of the term itself. There is already political resistance, including a proposed federal bill that would preempt states from imposing an exit tax.249 States can label the tax as a continuation tax, a benefit tax, trailing nexus, or simply not label it all. The exit tax would generally not be a standalone regime but would instead be an integral component of the state’s existing personal income tax regime.250 And if a state adopted a pure continuation tax approach, there would not be any new imposition of tax, just a new annual reporting obligation.