But he hasn't done anything yet, he just wants to. There's no legal standing for it at this point beyond what I said. Every case I've been able to find was tied to fraud associated with the naturalization process (either the process itself, or false statements given during the process).
Lack of legal standing is not something that has ever stopped this administration from doing something it has decided to do. Best case scenario is Miller gets thrown under the bus after the goal is accomplished.