In a historic win for climate activists, a Montana judge ruled in favor of 16 young plaintiffs, stating that the state was violating their constitutional rights by failing to consider climate change when approving fossil fuel projects.

District Court Judge Kathy Seeley ruled Monday that by allowing fossil fuel development, state agencies were violating a clause in the state constitution that guarantees “the right to a clean and healthful environment.”

The lawsuit — Held v. Montana — was the United States’ first constitutional climate trial, CNN reported.

How will the ruling affect future climate trials?

The ruling is a historic one because it represents the first time a U.S. court has ruled against the government for “violating a constitutional right based on climate change,” Harvard Law School Professor Richard Lazarus told The Associated Press.

“To be sure, it is a state court not a federal court and the ruling is based on a state constitution and not the U.S. Constitution, but it is still clearly a major, pathbreaking win for climate plaintiffs,” said Lazarus.

Julia Olson, the founder of Our Children’s Trust, the legal nonprofit that represented the plaintiffs, called the ruling a “game-changer” in the fight against climate change.

“This is a huge win for Montana, for youth, for democracy, and for our climate. More rulings like this will certainly come,” Olson said in a press release.

The ruling could set a legal precedent for similar cases at the state level.

Our Children’s Trust currently has climate cases in four other states: Florida, Hawaii, Utah and Virginia.

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Will the ruling stand?

The Montana attorney general’s office stated Monday that it would appeal the ruling, sending the case to the Montana Supreme Court.

“This ruling is absurd, but not surprising from a judge who let the plaintiffs’ attorneys put on a weeklong taxpayer-funded publicity stunt that was supposed to be a trial,” Emily Flower, spokesperson for the attorney general, said per AP. “Montanans can’t be blamed for changing the climate.”

If the ruling stands, Montana, which gets one-third of its energy from fossil fuels, according to The New York Times, must consider the impact on the climate when approving fossil fuel projects in the state.