Although no one knows exactly what the final form of the EPA rules will be, one thing is certain and that is EPA’s stated legal basis for the rules.
Even if that basis was to magically change in the final rule, it is EPA’s current rationale for the proposal. As such it should be fair game for challenge now.
After all, if EPA doesn’t have the legal authority to issue a proposal, then no proposal can be issued. That should be a justiciable issue now.