When people think of environmental law, they often think of statutory law and regulations. But parties sometimes seek to use other sources of law — such as the Constitution — to regulate the environment.

Last week, the Ninth Circuit issued a key ruling in Juliana v. United States, one such case, involving climate change. Plaintiffs – who are all between the ages of 10 and 21 – claim that the government’s policies toward carbon dioxide emissions and the use of fossil fuels violate their constitutional rights. Additionally, plaintiffs claim that the government’s policies violate the public trust doctrine, i.e. that the government has a duty to preserve national resources to benefit future generations, because carbon dioxide emissions permanently harm the Earth’s atmosphere.

Juliana made it to the Ninth Circuit after an Oregon district court rejected the U.S. government’s attempt to have the case dismissed. Instead of letting the case proceed through discovery and trial before the district court, the Justice Department petitioned the Ninth Circuit Court of Appeals for a writ of mandamus directing the Oregon district court to dismiss the case. The government’s mandamus request hinged in large part on the government’s belief that case discovery would be extremely burdensome.

On March 7, the Ninth Circuit denied the government’s mandamus request, finding that no “extraordinary circumstances” existed to support treating this case outside of the usual order and that the government’s mandamus request was “premature.” The court explained that “litigation burdens are part of our legal system,” and that even though the plaintiffs’ claims and proposed remedies were “quite broad,” the government still had options in district court to address the scope of the case. Given these options, it was important for the district court “to consider those issues further in the first instance.”

Last week’s ruling means that the case will proceed to trial in federal court. Stay tuned here for future developments.