In 2016, the incoming Trump Administration stated its intention to reduce substantially federal environmental regulation. The president issued executive orders requiring two rule repeals for each new rule and directing the reorganization of the U.S. Environmental Protection Agency (EPA). He also carried through on promises to announce the country’s withdrawal from the Paris Climate Accords and to reverse the Obama Administration’s controversial Waters of the U.S. Rule.

Now, the incoming Biden Administration has stated its intention to adopt a number of measures to address climate change, many of which entail reversing Trump Administration regulatory changes, either to the original or to some updated form. And even beyond those priorities, many commentators, including our podcast, our Government Law and Policy colleagues, and the New York Times have observed that the Biden Administration may roll back its predecessor’s environmental regulatory rollbacks much more broadly.

Four years ago, we advised at a webinar convened to discuss the incoming Trump Administration that the federal government was large and full of inertia and that changing environmental rules would be difficult and time-consuming. That remains true: rolling back regulations is uphill in both directions.

The Biden Administration, however, faces unique challenges to its regulatory agenda that the outgoing administration did not. Since fiscal year 2010, the EPA has lost more than 26% of its budget and 18% of its personnel. The Trump Administration retrenched the agency’s Science Advisory Board, reorganized broad swaths of the agency’s enforcement and program offices, and proposed profound changes to the civil service personnel system; many senior managers have either retired early or left the agency for the private sector. Calls to provide new resources to EPA will compete with COVID-19 response and economic relief.

The loss of institutional knowledge and bureaucratic skill makes bold change more challenging. After all, regulatory changes generally have to be adopted with all the procedure and formality of an initial rule adoption, whether they repeal or merely reinstate an old rule. And each change is subject to judicial review; it cannot be arbitrary, capricious, or contrary to law.

Courts recognize that elections have consequences, and a non-arbitrary shift in policy can justify a change in a rule. But an election itself is a less-ready justification for a change in the factual determinations underlying a rulemaking. In order to change factual findings, the agency typically requires additional evidence on which to base them.

The Trump Administration repealed or amended more than a hundred environmental rules. Many of those changes were the subject of litigation brought by opponents to the change, typically states and environmental advocacy groups. Much of that litigation remains pending. Any change in rules will likely reshuffle the parties or moot existing cases and induce a subsequent challenge to the Biden rulemaking.

The reinstitution of environmental regulation will be complicated, time-consuming, and litigated, just like the last four years of deconstruction have been. That poses uncertainty for regulated entities, but also multiple opportunities to influence the form of any new rules. The specific complexities are different for different changes, but look for actions in the areas of:

• climate change mitigation (reducing greenhouse gas emissions at sources and encouraging use of renewable fuels and power);

• climate change adaptation (moving infrastructure, increasing resilience, and so forth);

• the ongoing battle over the definition of Waters of the United States;

• environmental review, both general review under the National Environmental Policy Act generally, including re-visiting the recently promulgated re-write of the NEPA regulations, and specific reviews like state issuance of water quality certifications under section 401 of the Clean Water Act, also the subject of recent rulemaking;

• regulation of cars and trucks under the Clean Air Act (such as reissuance of the “California waiver”);

• regulation of extractive industries (such as methane emissions from oil and gas operations, changes in leasing, and so forth);

• regulation of the management of coal combustion residuals;

• chemical and pesticide regulation, including regulation of nanotechnology; and

• jurisdictional issues such as the Clean Air Act aggregation policy.

Rollbacks are somewhat easier when they merely involve issues of priorities and funding. Some approvals might move faster and some slower. For example, many believe that a Biden Bureau of Ocean Energy Management will review projects more quickly. Further, many expect a flurry of executive orders in the first weeks of the administration directed at, among other things, slowing or withdrawing rules that are not yet final.