In March, a federal district court case led to an unexpected spectacle: a “tutorial” on climate science requested by the judge. Oakland and San Francisco had filed suit against several oil companies, alleging that they should help pay for the impacts of sea-level rise because they had intentionally misled the public about global warming. Judge William Alsup apparently wanted to make sure he understood the physics and chemistry of the situation before he weighed legal standards.

On Monday, Alsup granted the defendants’ motion to dismiss the case—a blow for Oakland, San Francisco, and other cities eyeing the outcome. “The issue is not over science,” Alsup writes in his decision, “All parties agree that fossil fuels have led to global warming and ocean rise and will continue to do so.”

Instead, the decision turns on legal precedents and Alsup’s unwillingness to overstep what he views as the judicial branch’s role.