After the Supreme Court heard oral arguments Feb. 21 in major wetlands regulation cases, observers were parsing the justices’ comments for clues about how they would rule. The cases are the consolidated Rapanos v. U.S. and Carabell v. U.S. Army Corps of Engineers, as well as S.D. Warren Co. v. Maine Board of Environmental Protection.

M. Reed Hopper, attorney for plaintiff John Rapanos, called that case federal “agency overreaching.” But Solicitor General Paul Clement warned if federal regulatory scope is curbed, it could lead to a “free dump zone” for polluters.

The justices peppered both sides with a range of questions, including what sorts of water bodies federal authority covers. Chief Justice John Roberts said, “At some point, the definition of ‘tributary’ has to end.”