The opinion did nothing of the sort. It invalidated certain procedural regulations issued by the CEQ - on the basis that the CEQ was an advisory body only without authority to issue binding regulations - meaning, in particular, that the underlying enforcement agencies - the Parks Department and the FAA - could not take the position that current tourist flights over a bunch of federal parks did not require a full statement of environmental impact before a plan permitting those flights could be adopted by those two agencies - whose authority to issue environmental regulations was never questioned or put into doubt - and therefore that the two agencies have to go back to the drawing board and engage in a full environmental review of the environmental impact of the tourist flights.
So, instead of having a uniform set of rules governing the sorts of statements and environmental reviews required under the National Environmental Policy Act ("NEPA"), each agency will now pursue its own course of action, with some agencies permitting plans to go into effect without a drawn out environmental review, and other agencies requiring exquisitely detailed environmental review in all cases - which will simply stymie private parties if two agencies with inconsistent policies under NEPA both have jurisdiction over the same issue, such as happened in this case where both the Parks Department and the FAA had regulatory authority over these flights.
It should be noted that the decision does not undo one single iota of substantive environmental regulation, but it does balkanize the process for getting environmental plans approved when multiple agencies have concurrent jurisdiction.
