This post was originally published on SCOTUSblog. It is republished here under a Creative Commons license (CC BY-NC-ND 3.0 US).

The Supreme Court has concluded that Virginia's decades-old moratorium on uranium mining is not pre-empted by the Atomic Energy Act. But there is no clear answer to the question that pervaded the briefing and oral argument: What is the proper role for state legislative purpose in a pre-emption analysis?

Monday's judgment was accompanied by three opinions: a lead opinion written by Justice Neil Gorsuch and joined by Justices Clarence Thomas and Brett Kavanaugh; a concurring opinion by Justice Ruth Bader Ginsburg, joined by Justices Sonia Sotomayor and Elena Kagan; and a dissenting opinion by Chief Justice John Roberts, joined by Justices Stephen Breyer and Samuel Alito. The Gorsuch opinion stated that state legislative purpose has no place in pre-emption analyses, whereas the Ginsburg opinion expressed discomfort at such a hard-line stance. Roberts' dissent would have used evidence of state legislative purpose to find that Virginia's ban was pre-empted. Overall, Monday's opinions likely presage important battles to come on the matter of legislative purpose as the court's composition shifts — battles that will take place across a wide variety of subjects …