The future of the Clean Power Plan is still in question as the D.C. Circuit Court of Appeals has not yet issued its opinion in the case and the Trump administration is debating how to move forward. The U.S. Supreme Court stayed implementation of the Clean Power Plan pending judicial review on February 9, 2016. The D.C. Circuit Court of Appeals, sitting en banc, heard oral arguments in the case on September 27, 2016.

The D.C. Circuit could issue its decision on the existing rule at any time and has not provided any estimated date of when it will rule. Four power sector groups challenging the Obama EPA’s denials of their administrative petitions regarding the Clean Power Plan recently asked the D.C. Circuit to move their pending challenges into the already-argued litigation, raising the potential that the decision could be further delayed. However, environmental groups are fighting this request. Regardless of the D.C. Circuit’s decision, a petition for review to the Supreme Court will likely occur.

President Trump’s March 28, 2017 Executive Order directs EPA to review the Clean Power Plan and suspend, revise or rescind the rule as appropriate and consistent with law. EPA filed a motion asking the D.C. Circuit to hold the Clean Power Plan case in abeyance while it conducted its review pursuant to the Order. Environmental groups are expected to oppose this motion.

Other agency actions suggest EPA will likely assert it has authority to quickly change regulations related to the Clean Power plan. In a March 6 Federal Register notice regarding the Obama Clean Water Rule, EPA stated that Supreme Court precedent supports giving EPA the freedom to quickly revise and that agencies have inherent authority to change past decisions so long as the change is permitted by law and supported by a reasoned explanation, even without a change in facts or circumstances. Citing a 2012 decision from the United States Court of Appeals for the D.C. Circuit, EPA stated that a “change in administration brought about by the people casting their votes is a perfectly reasonable basis for an executive agency’s reappraisal of the costs and benefits of its programs and regulations.” EPA may choose to rely on this same precedent to quickly revise or revoke the Clean Power Plan.

Given the unknown future of the Clean Power Plan, both supporters and opponents of the rule have begun to prepare for future action. For example, in December 2016, EPA withdrew its draft final model trading rules for the Clean Power Plan from interagency review and publicly released the model and related guidance documents so states would have the information in developing their own climate initiatives. A group of Republican officials has launched an effort to build support for a carbon tax plan that could potentially revoke EPA’s authority to regulate greenhouse gases. As these examples demonstrate, the futures of the Clean Power Plan and, more generally, the regulation of greenhouse gases, are deeply in flux.