In Robinson Township v. Commonwealth of Pennsylvania, the Pennsylvania Supreme Court held unconstitutional major parts of Pennsylvania’s “Act 13”—a 2012 oil and gas law designed to facilitate the development of natural gas from Marcellus Shale. In so doing, the Court breathed new life into Article I, Section 27 of Pennsylvania’s constitution, which creates public rights in certain environmental amenities and requires the state to “conserve and maintain” public resources “for the benefit of all the people.” This paper describes the decision, explains some of its immediate implications in Pennsylvania, and also explains its importance for public environmental rights and environmental constitutionalism elsewhere.