The wording in Article IX, Section 1, of Montana’s constitution couldn’t be clearer: “The state and each person shall maintain and improve a clean and healthful environment in Montana for present and future generations.” Accordingly, in April, a district court judge in Yellowstone County voided a permit for a natural gas–fired power plant under construction there. Over its lifetime, it would have released an estimated twenty-three million tons of planet-roasting carbon dioxide, and that, ruled the judge, was incompatible with a “clean and healthful environment” in Montana or, for that matter, anywhere else.

Within a week, the state legislature had voted to reinforce a 2011 law barring the consideration of climate change in policymaking and so allowing the construction of the power plant to resume. But that wasn’t the end of the matter. Last month, the lawmakers were slapped down a second time when another district judge ruled in favor of a group of sixteen youthful Montanans in a suit filed in 2020 seeking to strike down that very 2011 anticlimate legislation.

In her ruling, Judge Kathy Seeley wrote, “Montana’s climate, environment, and natural resources are unconstitutionally degraded and depleted due to the current atmospheric concentration of [greenhouse gases] and climate change.” She added that “every additional ton of greenhouse gas emissions exacerbates Plaintiffs’ injuries and risks locking in irreversible climate injuries.” The state, she made it abundantly clear, is obligated to correct such a situation.