“For any [revision] of the Clean Power Plan, we would also expect a lengthy process by which the public has an opportunity to comment,” said Sanne Knudsen, an environmental law professor at the University of Washington. (The original Clean Power Plan received over 4 million comments.) “Those processes can take a few years… And then at the end of the process, we would expect to see judicial review and litigation.” - https://news.vice.com/story/trump-executive-order-guts-obama-era-environmental-protections