It was once well settled and uncontroversial—reflected in legislative enactments, Executive Branch practice, judicial doctrine, and the broader constitutional culture—that the Constitution imposed limits on government partisanship. This principle was one instantiation of a broader set of rule of law principles: that law is not merely an instrument of political power; that government resources should not be used to further partisan interests, or to damage partisan adversaries. For at least a century, each branch of the federal government has participated in the development and articulation of this nonpartisanship principle. In the legislative realm, federal statutes beginning with the 1883 Pendleton Act have dramatically limited the role of partisanship in federal employment decisions. Since 1939, the Hatch Act has reflected a related constitutional principle: just as most federal workers should not be selected or terminated on the basis of partisanship, neither should they be permitted to use their positions, once attained, for partisan pursuits. Executive Branch law and practice have long reflected a similar set of principles in the employment realm and beyond. The Supreme Court has also enforced a nonpartisanship principle across a range of cases, including the political patronage cases, in which the Court has announced and elaborated a constitutional requirement that most local government hiring, firing, and other employment decisions be made independent of partisanship. But these settled understandings, across institutions and bodies of law and practice, have come under attack in recent years. Over the course of his term in office, President Donald Trump grew increasingly willing to challenge nonpartisanship principles directly, culminating in his issuance of an executive order that would have given him the authority to reclassify large swaths of the federal workforce as outside of the civil service—an effort he has pledged to revive if given the chance. In perhaps less obvious ways, the ...