Section 103(c) of the statute sets out the limits of federal authority over state and Native lands in a district:

Only those lands within the boundaries of any conservation system unit which are public lands (as such term is defined in this Act) shall be deemed to be included as a portion of such unit. No lands which, before, on, or after the date of enactment of this Act, are conveyed to the State, to any Native Corporation, or to any private party shall be subject to the regulations applicable solely to public lands within such units.

And here’s where the dispute begins. Sturgeon—and the state of Alaska—argue that this language means that state lands are exempt from all National Park Service regulations. The government argues that the words “applicable solely to public lands” exempt only NPS regulations drawn up solely for one specific conservation unit. A National Park or Preserve area that includes state or Native land would still be governed by the general regulations for National Parks; but if the Service decides to regulate that specific parcel, the state and Native lands are exempt from those local regulations.

In the years after ANILCA was passed, the federal government agreed with the state’s interpretation—general park rules didn’t apply; but in 1996, the Service conducted a formal process to change the interpretation of the rule. After notice and comment by everyone involved, it adopted its current interpretation, and courts have upheld that reading. When Sturgeon came before the Ninth Circuit, a panel unanimously held that the statute “unambiguously” supports the NPS.

Americans in the East often underestimate how emotional the issue of public lands can be to those in the West. As Alaska points out in its amicus brief, only 4 percent of the total area east of the Mississippi is federal land (where seven of the nine Justices were born); in the 11 contiguous Western states, the overall figure is 47 percent. In Alaska, 61 percent of the state belongs to the federal government. (Alaska isn’t even the champion; the feds own 66.5 percent of Utah.)

Many Westerners believe that this land ought to belong to them, to be used without interference from Washington. Conservatives intuitively sympathize with the locals. That ideological predisposition may be behind the Court’s decision to hear this case, which land-use experts regard as puzzling. “I was very surprised that the Court thought there was anything here of importance,” John Leshy of Hastings College of the Law, a former solicitor of the Interior Department in the Carter administration, said in an interview last week. “It has no legs.” Any result will have an impact only in Alaska, Leshy noted, because it hinges on an interpretation of ANILCA, which applies only there. Finding a constitutional issue—one that would in some way affect federal authority elsewhere in the West—would require a stretch far beyond the facts and the briefing.

The Court, however, can do anything it wants, and some of the justices may be seeking a chance to make a statement about federal management of Western lands—an issue that is hovering in the background.