The Donald Trump Administration has been attempting to roll back a wide array of regulations, including rules that have governed methane emissions, established energy-efficiency standards, and defined “waters of the United States.” The U.S. administrative law framework allows rules to be changed or undone, but governs how these modifications can happen. In most cases, the Administrative Procedure Act (APA) mandates justifications similar to those required for an original rulemaking if a regulation is to be cancelled or rescinded. If an agency seeks to disregard the factual record on which an original rule rests, it must provide a more detailed justification for the change, and satisfy additional requirements. Suspending rules or delaying their effective date also places procedural obligations on agencies. On May 16, 2018, ELI convened experts to discuss obstacles to deregulation, including when and how an agency must consider costs and benefits of staying, repealing, and rewriting rules. Speakers commented on current challenges to the Trump Administration’s deregulation agenda, and offered insights on the ways administrative law is developing through interpretation of the APA and other relevant statutes. This article presents a transcript of the discussion, which has been edited for style, clarity, and space considerations.