If as Oscar Wilde said “experience is simply the name we give our mistakes,” then the U.S. Environmental Protection Agency (EPA) has had plenty of experience trying to regulate interstate air emissions. The Cross-State Air Pollution Rule (CSAPR) was simply EPA’s most recent attempt. It was short-lived. The D.C. Circuit vacated CSAPR in EME Homer City Generation, L.P. v. EPA, 696 F.3d 7 (D.C. Cir. 2012) before the rule could even take effect.