Editors' Summary: Supreme Court review in Chevron U.S.A., Inc. v. Natural Resources Defense Council, Inc. and congressional reauthorization offer the possibility at last of clarification of the role of the bubble policy in implementing the Clean Air Act. Professor Rhinelander reviews the administrative and judicial histories of the bubble policy, concluding that it should be applied liberally, but that Congress and the D.C. Circuit have left too many obstacles in EPA's path. Turning to the pending Supreme Court action, he argues that the court can and should tear down an unnecessarily large barrier recently erected by the D.C. Circuit but that only amendments to the Act will allow realization of the full potential of the bubble policy.