On May 25, 2023, the U.S. Supreme Court dropped an absolute bombshell with its ruling in Sackett v. Environmental Protection Agency. Early assessments of Sackett underscore two vital points: much has been lost for wetlands protection, and much has changed with respect to the Court’s broader environmental law jurisprudence. This Comment delves into both of these issues, providing some background on the unique and long-running controversy that was at the heart of Sackett, and parsing the four opinions from the case. It then looks at one of the Supreme Court’s landmark decisions on agency expertise and wetlands, United States v. Riverside Bayview Homes, arguing that Riverside Bayview Homes, a unanimous decision that environmentalists, courts, and the regulated community have relied on since 1985, is now a dead letter. Finally, it looks at the road ahead, considering how the decision in Sackett will filter down (pun intended) to affect other environmental values.