Among the Trump Administration's more controversial regulations was an Environmental Protection Agency rule that narrowed the ability of states to block projects by denying certification under Section 401 of the Clean Water Act. This rule was intended to make it more difficult for states to block infrastructure projects by refusing to certify that granting a federal permit or license would not prevent attainment of a state's water quality standards.
As one would expect, blue states and environmental organizations challenged the Trump EPA's Section 401 rule. Because the rule was not issued until July 2020, the challenges were still pending in district court when the Biden Administration entered office. As one woud also expect, the Biden Administration announced in June 2021 that it would reconsider the Trump EPA's 401 rule.
In light of its plan to reconsider the 2020 rule, the EPA asked the district court for a voluntary remand. As is common with such requests, the EPA also asked the district court to leave the rule in place while it was being reconsidered. The plaintiffs, however, disagreed, and argued that the district court should either deny the remand request or grant it in conunction with an order vacating the rule. The district court adopted the latter course, leading to this appeal. (Also of note, the Supreme Court also stayed the district court's order vacating the rule, by a vote of 5-4, pending the outcome of the appeal.)
