Chief Justice John Roberts challenged Oklahoma's position that its state sovereignty would somehow be violated if Texas took water from within its boundaries.
“Compacts compromise the individual state sovereignty,” Roberts told Blatt, Oklahoma's attorney. “That's the whole point of them.”
Some justices also expressed interest in what would happen if Oklahoma had to give permits to Texas applicants — that is, how they would be prioritized.
Rothfeld said Texas applicants would just go through the same process that Oklahoma ones do now, while Blatt noted that Oklahoma's system allows priority to the first users.
“There are four Texas entities that have signed up for permits. … And poor Oklahoma City got sandwiched in the middle,” Blatt said.
The Obama administration agrees with the Tarrant water district on the key point of whether Texas can get its share of the excess water from Oklahoma, and the administration says Oklahoma's laws barring the export of water out of state violate the compact.
However, it diverges with Texas on another key point — whether Texas must first get its share from within its own borders before going into Oklahoma.
The Tarrant district argues that it can get all of its share from Oklahoma, despite what exists in Texas.
“Under our theory … if Texas was already receiving 25 percent of the water, then Oklahoma would not have to give it any kind of special priority,” Justice Department attorney Ann O'Connell told the justices on Tuesday.
Oklahoma Attorney General Scott Pruitt sat with the other Oklahoma attorneys in the courtroom on Tuesday and said afterward that “it's always difficult to know where a court is headed by the questions they ask.”
Pruitt said he was encouraged by justices' interest in the lack of explicit language allowing Texas to cross the border for water.
Oklahoma would never have granted that permission, Pruitt said, without including the mechanics involved, such as the diversion point of the water and how property could be taken by eminent domain.
Rothfeld, the attorney for the Texas agency, also said he couldn't read the justices' minds from the arguments.
He said some of the questions regarding how Oklahoma would process applications from Texas reflected the court's lack of exposure to water compact cases.
Rothfeld said it would be difficult for the court to dispose of the case without deciding whether the compact allows Texas to get its share of water in Oklahoma.
“Can Oklahoma categorically exclude Texas users from getting their water in Oklahoma?” Rothfeld said. “I think they do have to answer that question.”