I've been wondering all year about what happens when an executive-branch office issues orders that it is not legally qualified to issue; by and large everybody has just... followed them. This may be another example (I don't know quite enough of the legal specifics in this case, though there are certainly others that are more slam-dunk-y in this respect).
What are the enforcement mechanisms here if the states in question---MA, RI, CT, NY, NJ, and VA---just said "no go ahead, keep building"? What happens to the companies if they just keep building? I'm not saying they should but at this point rule-of-law has fallen apart so badly that I literally don't know what happens when the government invents a new rule and people just... disregard it. (Particularly if state-level enforcement decides not to play along.) Do they bring in the FBI? Military?