PORTLAND, Ore. — Attorneys for 21 young Americans who accuse the U.S. government of violating their constitutional right to a safe and livable climate said they are hopeful that they’ll get to take their case to trial after a pivotal appeals court hearing Tuesday.

During the intense one-hour session before the 9th Circuit Court of Appeals, three judges asked numerous questions about the type of remedy the court might provide to address the injuries the young plaintiffs say they have suffered because of government actions that exacerbated global warming.

“Remedy comes at the end of the case,” said Philip Gregory, a lead attorney for the plaintiffs. He said he felt “very positive” about the day’s proceedings.

The plaintiffs say climate change has ruined their homes by making storms more extreme; worsened their respiratory health by generating more wildfire smoke and longer pollen seasons; and caused psychological distress as they face the prospect of growing up in a fundamentally changed world. In their lawsuit, they claim the government bears responsibility for infringing their rights to life, liberty and property through its ongoing support of fossil fuels, the primary driver of climate change.

Specifically, the suit points to the greenhouse gas emissions that result from policies like leasing federal lands for coal mining and oil and gas extraction, setting lax vehicle emission standards, and subsidizing the fossil fuel industry.

Direct U.S. subsidies, such as tax credits, total $20 billion per year, according to a 2017 analysis by Oil Change International, a group that advocates for clean energy. And indirect subsidies, like allowing emitters to avoid paying for the true cost of air pollution, raise the number to $650 billion annually, the International Monetary Fund calculated in a recent report.

Government lawyers argue that the case had numerous flaws, each of which should disqualify it from proceeding to trial. Among them: There is no constitutional right to a stable climate, and the youth should challenge federal policies under the Administrative Procedure Act instead of through a lawsuit.

Jeffrey Clark, who represented the government, called the case “a direct attack on the separation of powers.” Government lawyers have long maintained that Congress and the president should set climate policy, and that the courts have no business getting involved.

But Judge Andrew Hurwitz pushed back with a hypothetical scenario. What if raiders were kidnapping children and murdering them, and the executive branch did nothing? “Should the courts intervene?”

Clark said the answer was no. “However painful that might be,” the remedy would be to remove the unresponsive lawmakers from office, he said.

At first, Hurwitz characterized the case as being about government inaction, and asked whether that could deprive someone of their rights.

Julia Olson, the lead attorney with Our Children’s Trust, the organization representing the youth, responded that the case was in fact about the government’s affirmative actions —like allowing fossil fuels to be extracted from public lands and permitting pipelines to be built.

Mary Wood, a law professor at the University of Oregon who wrote an amicus brief supporting the plaintiffs, said she thought the judges were persuaded by that element of Olson’s argument. “There was an epiphany,” she said.

It’s less clear whether the judges agree that the Constitution protects a right to a safe and livable climate. Olson argued that this right is already enshrined in the Fifth amendment’s protections, and don’t require the court to break new ground. But Hurwitz disagreed.

“You shouldn’t say this is an ordinary suit,” he said. “You are asking us to do a lot of new stuff.”