The Trump administration's efforts to block a major climate change lawsuit that was brought on novel grounds by a group of young people appeared to suffer a setback Monday at a hearing before a federal appeals court.

The lawsuit, Juliana v. United States, was filed in 2015 on behalf of 21 youths who are accusing the government of violating their constitutional rights by failing to address climate change and continuing to subsidize fossil fuels.

A federal district judge earlier this year set a trial date for February. But in July, the Ninth Circuit Court of Appeals paused the case after the Justice Department invoked an unusual legal maneuver to try to block the lawsuit.

On Monday, two of the three judges on the panel seemed dubious of the move.

Michael Gerrard, director of the Sabin Center for Climate Change Law at Columbia University, has been following the case and said the judges' questions and comments on Monday suggested they would send the case back to the district court and allow it to proceed. "They said it's too early to be here," Gerrard said.

Last year, the district judge denied the government's motion to dismiss the case. After President Donald Trump took office, however, the Justice Department asked for a writ of mandamus—essentially an order from an appeals court to a lower one, generally to correct an abuse. The Department of Justice contended in its petition that the district court had "rendered unprecedented and clearly erroneous rulings" by failing to dismiss the case and had demonstrated "a remarkable disregard for essential separation-of-powers limitations."

At the hearing on Monday in San Francisco, Chief Judge Sidney R. Thomas, who was appointed by President Bill Clinton, said there was no precedent for issuing such a writ under these conditions and that if the judges did issue it, there would be "no logical boundary to it."

The plaintiffs are seeking to establish a constitutional right to a stable climate, and they're asking the courts to order the federal government to rapidly cut the nation's greenhouse gas emissions.

Another judge, Alex Kozinski, who was appointed by President Ronald Reagan, pressed Julia Olson, the lawyer for the children and executive director of the advocacy group Our Children's Trust, on the merits of the case.

After these oral arguments, the judges will now have to decide whether to intervene. If they send the case back to the district court, Gerrard expects the Justice Department would look for other ways to prevent the case from going to trial, where the government could be forced to produce documents and depositions that could reveal deliberations on decades of federal climate policies.

When asked whether the plaintiffs have a shot, Gerrard said, "they have a better shot today than they did yesterday."