Residents of Flint, Mich., have no constitutional right to clean water, attorneys for Michigan told a federal appeals court June 6, arguing that a ruling against the state could open it to a tidal wave of further lawsuits.

That issue underpinned an hour of oral arguments June 6 before a three-judge panel of the U.S. Court of Appeals for the Sixth Circuit. The question of the government’s immunity in a water crisis rests in the judges’ hands, and they dug into whether officials committed a clear constitutional violation necessary to defeat immunity.

“Where is the constitutional violation, because...