The U.S. Supreme Court on Monday sidestepped a major constitutional decision on federal-state powers, ruling that a federal law implementing a chemical weapons treaty cannot be applied to a local dispute triggered by a Pennsylvania woman’s effort to injure her husband’s lover.

“The global need to prevent chemical warfare does not require the federal government to reach into the kitchen cupboard, or to treat a local assault with a chemi­cal irritant as the deployment of a chemical weapon,” Chief Justice John Roberts Jr. wrote for the court. No justice dissented, but several wrote concurring opinions.