Chevron asked a federal appeals court Wednesday to move a Plaquemines Parish coastal damage case into federal court, a step the company says would erase a $744.6 million state jury verdict against it.

The lawsuit accuses Chevron’s predecessor of dumping billions of gallons of wastewater into Louisiana marshes during decades of oil production.

Wednesday’s arguments were not about whether Chevron caused the damage. The judges were instead asked to decide whether the case should now be moved to federal court and, if so, whether the state trial and jury verdict must be thrown out.

Chevron attorney Paul Clement pointed to the recent unanimous U.S. Supreme Court ruling that was handed down earlier this year. He said the decision makes it “obvious” that the Plaquemines case belongs in federal court because some of the oil production and refining at issue was tied to federal contracts during World War II.

“The unmistakable message from the Supreme Court in the Chevron case is that these cases belong in federal court,” Clement told the judges.

Chevron argues that a federal judge wrongly sent Plaquemines Parish’s lawsuit back to state court in 2023. The case was later tried before a Plaquemines Parish jury, which awarded $744.6 million. Chevron now says that reversing the 2023 decision would invalidate that trial and verdict.

Louisiana disagrees. The state says the Supreme Court decided only that the lawsuit was sufficiently connected to federal wartime work to satisfy one requirement. A federal trial judge must still decide whether Chevron waived its right to move the case, whether its World War II contract argument is valid and whether it has a legitimate federal defense.

The appeals court should take the limited step of returning the case to the federal trial judge, rather than deciding every unresolved issue itself, the state argues.

"That is all the court need do."

The state also says Chevron gave up its right to demand a federal trial by participating fully in the state case.

Chevron filed motions, went through a month-long trial and later asked the state judge to enter a final judgment reflecting the jury’s award. Before the trial, Chevron told the court it was “ready and eager to try the case.”

“Only now—after Appellants experimented in the state court and did not like the results—have they decided to try to escape state court again,” Louisiana’s brief said.

Clement responded that Chevron had continued to argue throughout the case that it belonged in federal court. He said the company should not have been required to stop defending itself in state court while that dispute remained unresolved.

The appeals judges repeatedly questioned what would happen if they ruled for Chevron. One judge asked whether the court could “effectively nullify all of the state court proceedings” after the company had participated in a full trial.

“The short answer is this court absolutely has the power to do that,” Clement replied.

The Fifth Circuit did not immediately rule. It could move the case into federal court, send it back to a federal trial judge for further review or leave the state proceedings in place.