(CN) - The U.S. Supreme Court on Wednesday allowed two non-state entities to intervene in a dispute between North Carolina and South Carolina over the water rights to the Catawba River, but ruled that Charlotte, N.C., lacks a "compelling interest" to join the action.
The justices rejected the intervention rule that had been created by a special master, who allowed three non-state entities to join the lawsuit based on their "compelling circumstances."
The high court found this rule too broad.
"[A] compelling reason for allowing citizens to participate in the original action is not necessarily a compelling reason for allowing citizens to intervene in all original actions," Justice Samuel Alito wrote for the majority.
But the court held that two of the intervening parties - the Catawba River Water Supply Project and Duke Energy Carolinas - met the standards for intervention, even though Charlotte did not.
"Charlotte has not carried its burden of showing a sufficient interest for intervention in this action," Alito concluded.
"Its interest is solely as a user of North Carolina's share of the Catawba River's water."
Chief Justice John Roberts also rejected the special master's rule, but said the other entities should have been likewise barred from intervening.
"The result is literally unprecedented," Roberts wrote. "Even though equitable apportionment actions are a significant part of our original docket, this court has never before granted intervention in such a case to an entity other than a State, the United States, or an Indian tribe. Never."
That's because apportionment "is a sovereign dispute," he wrote, "and the key to intervention in such an action is just that - sovereignty."
Justices Clarence Thomas, Ruth Bader Ginsburg and Sonia Sotomayor joined Roberts' concurrence and partial dissent.
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