Ahead of an upcoming Supreme Court case, the U.S. Environmental Protection Agency is standing by the allegedly “vague” permit that it issued to San Francisco allowing it to discharge sewage into the Pacific Ocean, and downplaying the risk that it exposes the city to ruinous liability.

The case, San Francisco v. EPA, is the second time in two terms that the famously liberal-leaning West Coast municipal government has found itself at odds with the Biden administration in a legal issue at the nation’s top court.