Abstract: The purpose of this Essay is to propose and discuss the possibility that the nation currently faces another, albeit very different, "republican moment" that may well test the future of environmental protection laws in the United States. This new "moment" has as its modifier an uppercase "Republican" rather than a lowercase "republican." While the latter "republican" invokes the political tradition referred to as "civic republicanism," the former "Republican" refers instead to the current National Republican Party. The "moment" facing environmental law is the virtually unprecedented ascendancy of the Republican Party in all three branches of the federal government.