President Obama issued an executive order containing a climate action plan that directed EPA to reduce greenhouse gas emissions from power plants that produce electricity. The Clean Power Plan was the culmination of that executive action. It was a regulation promulgated under EPA’s authority to reduce the amount of fossil fuels that would be combusted for power in favor of renewable sources. Traditionally, most electricity in the United States was made through combusting coal or natural gas and power plants. The Clean Power Plan required a significant reduction in the amount of energy that could be generated in that way. It’s not really a pollution control program, it is an energy policy program. Throughout the country, citizens are unhappy with the prospect of losing jobs and higher energy prices. States who were affected were also unhappy and, of course, industries that were directly impacted. the challengers took the unusual step of going to the Supreme Court and asking for a Supreme Court stay. For the first time ever, in a case like this, the Supreme Court granted that stay. On the question of whether the Clean Power Plan is lawful, the best arguments rely on five words in the text of Section 111 of the Clean Air Act: “Best system of emission reduction,” in quotes and EPA, in its litigation, did an admirable job of looking at that little phrase and saying well, the Clean Power Plan gives states time to comply, it gives states flexibility in how they want to reduce carbon-based power generation. One of the biggest questions in energy policy over the last several decades was the extent to which the United States wanted to move to a zero carbon or lower carbon power economy through renewable sources and nuclear energy. There have been bills introduced every Congress for at least the last 20 years that would require this shift. None have passed. In a case a few years ago the Supreme Court said that when an administrative agency claims to find a broad power in a long existing statute, we look skeptically on it. For over 40 years, the Clean Air Act has been a pollution control program not an energy policy program. Regulations can be undone by successor administrations. Executive orders can be undone by successor presidents. As much as this issue was a priority for President Obama, reversing it may well end up a priority of President Trump.