In a setback to environmentalists, the U.S. Supreme Court today limited the scope of the Clean Water Act, saying that an Illinois solid waste agency could locate a trash dump in a remote wetland area used by migratory birds. The U.S. Army Corps of Engineers had blocked the landfill, claiming authority to do so under the act because the dump would affect interstate commerce, notably the bird-watchers and hunters who travel across state lines in search of species found in the wetland area. Writing for the 5-4 majority, Chief Justice William Rehnquist disagreed with the agency’s decision, but seemed to take pains to keep his opinion focused on the case at hand, not on broader questions about whether environmental regulations stretch the definition of interstate commerce. Justice John Paul Stevens, writing for the minority, said, “Today the court takes an unfortunate step that needlessly weakens our principal safeguard against toxic water.”