Attorneys contesting the future of a massive Red River flood diversion project for Fargo-Moorhead spent three hours Tuesday arguing whether the project should be paused pending a permit from Minnesota.

In litigation that has dragged on since 2013, the latest chapter centers on Minnesota's sovereignty to regulate its own land and the implications of a judge halting work done, in part, by the U.S. Army Corps of Engineers.

Max Kieley, an attorney representing the Minnesota Department of Natural Resources (DNR), which joined the case late last year, told Chief U.S. Judge John Tunheim that the corps and a local diversion authority undercut the DNR. Minnesota, he said, is not "a construction first, permit later state."

"It's even truer in a complex, $2.2 billion flood control project that spans two [states]," Kieley said.

The gallery of St. Paul's largest federal courtroom was at capacity Tuesday, with citizens from communities on opposite sides of the river taking nearly every seat.

A group of upstream residents sued in 2013 to stop the project, which includes a ring dike around three small North Dakota towns, a 36-mile diversion channel and a high-hazard dam meant to protect Fargo and Moorhead from floods that have hit the Red River Valley for 51 out of the past 113 years. The group wants a cheaper project that doesn't call for new dams that risk flooding thousands of acres in Minnesota.

The Fargo-Moorhead Diversion Authority, the legal authority behind the project, began construction in North Dakota despite Minnesota's refusal to grant a permit for a high-hazard dam that would bridge the two states. The authority said the U.S. Army Corps of Engineers has federal approval and does not need Minnesota's approval.

Devon McCune, a Justice Department lawyer representing the corps, said Tuesday that work in Minnesota is not slated to begin until at least 2019.

The plaintiffs are arguing that any part of the project first needs a permit from Minnesota, because of land affected on its side of the border, and want Tunheim to halt construction.

"It's a huge deal to spend hundreds of millions of dollars on something that's not going to be permitted, and then try to find a way out of that," said Gerald Von Korff, an attorney for the upstream residents' group. Minnesota would pay $100 million under the diversion plan.

Robert Cattanach, who represents the diversion authority, described the conflict as a "delicate moment in time" while two communities await flood protection. "Your decision on this motion will determine whether Moorhead and Fargo will get flood protection anytime in the near future," he told Tunheim.

Cattanach also pointed to an additional $60 million in construction costs each year the project is delayed. "Why are we even rolling these dice?" he asked.

McCune meanwhile warned that if Tunheim rules for the plaintiffs, he would be issuing a "broad waiver of sovereign immunity not just for this project but almost all projects the Corps is working on." The effect, she said, would be a surge in agencies dragged into courtrooms.

Tunheim said he expects to issue a ruling within the next 30 days.

Stephen Montemayor • 612-673-1755

Twitter: @smontemayor