The powers not delegated to the United States by the Constitution, nor prohibited by it to the States, are reserved to the States respectively, or to the people.
Since the mid-1970s, the Court has been closely divided over whether the Tenth Amendment or related constitutional doctrine constrains congressional authority to subject state activities and instrumentalities to generally applicable requirements enacted pursuant to the commerce power. 1 According to Garcia v. San Antonio Metropolitan Transit Authority, 2 the Tenth Amendment imposes practically no judicially enforceable limit on generally applicable federal legislation, and states must look to the political process for redress. Garcia, however, like National League of Cities v. Usery, 3 the case it overruled, was a 5-4 decision, and there are later indications that the Court may be ready to resurrect some form of Tenth Amendment constraint on Congress. 4
In National League of Cities v. Usery, the Court conceded that the legislation under attack, which regulated the wages and hours of certain state and local governmental employees, was
undoubtedly within the scope of the Commerce Clause, 5 but it cautioned that
there are attributes of sovereignty attaching to every state government which may not be impaired by Congress, not because Congress may lack an affirmative grant of legislative authority to reach the matter, but because the Constitution prohibits it from exercising the authority in that manner. 6 The Court approached but did not reach the conclusion that the Tenth Amendment was the prohibition here, not that it directly interdicted federal power because power which is delegated is not reserved, but that it implicitly embodied a policy against impairing the states’ integrity or ability to function. 7 But, in the end, the Court held that the legislation was invalid, not because it violated a prohibition found in the Tenth Amendment or elsewhere, but because the law was
not within the authority granted Congress. 8 In subsequent cases applying or distinguishing National League of Cities, the Court and dissenters wrote as if the Tenth Amendment was the prohibition. 9 Whatever the source of the constraint, it was held not to limit the exercise of power under the Reconstruction Amendments. 10
The Court overruled National League of Cities in Garcia v. San Antonio Metropolitan Transit Authority. 11 Justice Blackmun’s opinion for the Court in Garcia concluded that the National League of Cities test for
integral operations in areas of traditional governmental functions had proven
both impractical and doctrinally barren, and that the Court in 1976 had
tried to repair what did not need repair. 12 With only passing reference to the Tenth Amendment, the Court nonetheless clearly reverted to the Madisonian view of the Amendment reflected in United States v. Darby. 13 States retain a significant amount of sovereign authority
only to the extent that the Constitution has not divested them of their original powers and transferred those powers to the Federal Government. 14 The principal restraints on congressional exercise of the commerce power are to be found not in the Tenth Amendment or in the Commerce Clause itself, but in the structure of the Federal Government and in the political processes. 15
Freestanding conceptions of state sovereignty such as the National League of Cities test subvert the federal system by
invit[ing] an unelected federal judiciary to make decisions about which state policies it favors and which ones it dislikes. 16 Although continuing to recognize that
Congress’s authority under the Commerce Clause must reflect [the] position . . . that the States occupy a special and specific position in our constitutional system, the Court held that application of Fair Labor Standards Act minimum wage and overtime provisions to state employment does not require identification of these
affirmative limits. 17 In sum, the Court in Garcia seems to have said that most but not necessarily all disputes over the effects on state sovereignty of federal commerce power legislation are to be considered political questions. What it would take for legislation to so threaten the
special and specific position that states occupy in the constitutional system as to require judicial rather than political resolution was not delineated.
The first indication was that it would take a very unusual case indeed. In South Carolina v. Baker, the Court expansively interpreted Garcia as meaning that there must be an allegation of
some extraordinary defects in the national political process before the Court will apply substantive judicial review standards to claims that Congress has regulated state activities in violation of the Tenth Amendment. 18 A claim that Congress acted on incomplete information would not suffice, the Court noting that South Carolina had
not even alleged that it was deprived of any right to participate in the national political process or that it was singled out in a way that left it politically isolated and powerless. 19 Thus, the general rule was that
limits on Congress’s authority to regulate state activities . . . are structural, not substantive – i.e., that States must find their protection from congressional regulation through the national political process, not through judicially defined spheres of unregulable state activity. 20
Later indications were that the Court may have been looking for ways to back off from Garcia. One device was to apply a
clear statement rule requiring unambiguous statement of congressional intent to displace state authority. After noting the serious constitutional issues that would be raised by interpreting the Age Discrimination in Employment Act to apply to appointed state judges, the Court in Gregory v. Ashcroft 21 explained that, because Garcia
constrained consideration of
the limits that the state-federal balance places on Congress’s powers, a plain statement rule was all the more necessary.
[I]nasmuch as this Court in Garcia has left primarily to the political process the protection of the States against intrusive exercises of Congress’s Commerce Clause powers, we must be absolutely certain that Congress intended such an exercise. 22
The Court’s 1992 decision in New York v. United States 23 may portend a more direct retreat from Garcia. The holding in New York, that Congress may not
commandeer state regulatory processes by ordering states to enact or administer a federal regulatory program, applied a limitation on congressional power previously recognized in dictum 24 and in no way inconsistent with the holding in Garcia. Language in the opinion, however, seems more reminiscent of National League of Cities than of Garcia. First, the Court’s opinion by Justice O’Connor declares that it makes no difference whether federalism constraints derive from limitations inherent in the Tenth Amendment, or instead from the absence of power delegated to Congress under Article I;
the Tenth Amendment thus directs us to determine . . . whether an incident of state sovereignty is protected by a limitation on an Article I power. 25 Second, the Court, without reference to Garcia, thoroughly repudiated Garcia’s
structural approach requiring states to look primarily to the political processes for protection. In rejecting arguments that New York’s sovereignty could not have been infringed because its representatives had participated in developing the compromise legislation and had consented to its enactment, the Court declared that
[t]he Constitution does not protect the sovereignty of States for the benefit of the States or State governments, [but instead] for the protection of individuals. Consequently,
State officials cannot consent to the enlargement of the powers of Congress beyond those enumerated in the Constitution. 26 The stage appears to be set, therefore, for some relaxation of Garcia’s obstacles to federalism-based challenges to legislation enacted pursuant to the commerce power.
Extending the principle applied in New York, the Court in Printz v. United States 27 held that Congress may not
circumvent the prohibition on commandeering a state’s regulatory processes
by conscripting the State’s officers directly. 28 Printz struck down interim provisions of the Brady Handgun Violence Protection Act that required state and local law enforcement officers to conduct background checks on prospective handgun purchasers.
The Federal Government may neither issue directives requiring the States to address particular problems, nor command the States’ officers . . . to administer or enforce a federal regulatory program. It matters not whether policymaking is involved, and no case-by-case weighing of the burdens or benefits is necessary; such commands are fundamentally incompatible with our constitutional system of dual sovereignty. 29
In Reno v. Condon, 30 the Court distinguished New York and Printz in upholding the Driver’s Privacy Protection Act of 1994 (DPPA), a federal law that restricts the disclosure and resale of personal information contained in the records of state motor vehicles departments. The Court returned to a principle articulated in South Carolina v. Baker that distinguishes between laws that improperly seek to control the manner in which states regulate private parties, and those that merely regulate state activities directly. 31 Here, the Court found that the DPPA
does not require the States in their sovereign capacities to regulate their own citizens, but rather
regulates the States as the owners of databases. 32 The Court saw no need to decide whether a federal law may regulate the states exclusively, because the DPPA is a law of general applicability that regulates private resellers of information as well as states. 33
The Court's most recent consideration of the anti-commandeering principle occurred in 2018 in Murphy v. NCAA.  34 In Murphy, Justice Alito, writing on behalf of the Court, invalidated on anti-commandeering grounds a provision in the Professional and Amateur Sports Protection Act (PASPA) that prohibited states from authorizing sports gambling schemes.  35 Noting the rule from New York and
In holding that Congress cannot command a state legislature to refrain from enacting a law, the Murphy Court reconciled its holding with two related doctrines.  40 First, the Court noted that while cases like Garcia, Baker, and Condon establish that the anti-commandeering doctrine "does not apply when Congress evenhandedly regulates activity in which both States and private actors engage,"  41 PASPA's anti-authorization provision was, in contrast, solely directed at the activities of state legislatures.  42 Second, the Court rejected the argument that PASPA constituted a "valid preemption provision" under the Supremacy Clause.  43 While acknowledging that the "language used by Congress and this Court" with respect to preemption is sometimes imprecise,  44 Justice Alito viewed "every form of preemption" to be based on a federal law that regulates the conduct of private actors—either by directly regulating private entities or by conferring a federal right to be free from state regulation.  45 In contrast, PASPA's anti-authorization provision did not "confer any federal rights on private actors interested in conducting sports gambling operations" or "impose any federal restrictions on private actors."  46 As a result, the Murphy Court viewed the challenged provision to be a direct command to the states in violation of the anti-commandeering rule.  47