The U.S. Supreme Court on Thursday severely curtailed protections for "waters of the United States."

The decision in Sackett v. the U.S. Environmental Protection Agency (EPA) is "unanimous in result but very split in reasoning," explained Slate's Mark Joseph Stern. "The upshot of Sackett is that, by a 5–4 vote, the Supreme Court dramatically narrows" which wetlands are covered by the Clean Water Act.

The majority opinion — authored by Justice Samuel Alito and joined by all of the court's other right-wing members except Justice Brett Kavanaugh — concludes that the Clean Water Act only applies to wetlands with "a continuous surface connection" to larger bodies of water, excluding those that are "adjacent."