A groundbreaking climate lawsuit brought by 16 children in Montana more than three years ago goes to trial this morning. The plaintiffs, now 5 to 22 years old, argue Montana’s fossil fuel-friendly policies violate the state’s 1972 constitution’s guaranteed right to “a clean and healthful environment.” The state has opposed the lawsuit so far on procedural grounds.

The judge in the case has already stated she will not issue prescriptive policies the state must enact, if the plaintiffs were to win, but would instead issue an order declaring it had violated its own constitution. Such a ruling, however, could be a major boon to similar lawsuits across the country. “It will change the future of the planet if courts will start declaring the conduct of government unconstitutional,” Julia Olson, founder of Our Children’s Trust, the nonprofit that filed the lawsuit on the plaintiffs’ behalf, told the AP.

The fact that the case is going to trial at all, is itself significant, Rebecca Bratspies, director of the CUNY School of Law’s Center for Urban and Environmental Reform, told the Wall Street Journal. “I don’t think there was a sense until somewhat recently that litigation in courts, under state constitutions, might be a path forward.” Co-plaintiff Claire Vlases told Grist that “I’ve done as much as I think I can do as a person. And now I believe it’s time for my government to take action.” (AP, Wall Street Journal $, E&E News, Reuters, Grist, Truthout, TIME)