Dual federalism is a theory of federal constitutional law in the United States according to which governmental power is divided into two separate spheres. One sphere of power belongs to the federal government of the United States while the other severally belongs to each constituent state. Each sphere is mutually equal, exclusive, and limiting upon the other sphere, and each entity is supreme within its own sphere.
Under this theory, provisions of the Constitution such as the Commerce, Necessary and Proper, and Supremacy Clauses are interpreted, construed, and applied in a manner to maximize the authority of each government within its own respective sphere, while simultaneously minimizing, limiting, or negating its power within the opposite sphere. Within such jurisprudence, the federal government has authority where the Constitution so grants. In this case, there is a large group of powers belonging to the states or the people, and the federal government is limited generally to only those powers listed in the Constitution.
Cooperative federalism is a concept of federalism in which national, state, and local governments interact cooperatively and collectively to solve common problems, rather than making policies separately but more or less equally (such as the nineteenth century's dual federalism) or clashing over a policy in a system dominated by the national government.
In the American federal system, there are limitations on national government's ability to carry out its policies through the executive branch of state governments.
For example, in Printz v. United States (1997) the Court held that the national government could not directly require state law enforcement officers to conduct background checks under the Brady firearms legislation. The court explained that prior decisions warned that:
". . . this Court never has sanctioned explicitly a federal command to the States to promulgate and enforce laws and regulations."
Yet, there are significant advantages in a federal system to obtain state assistance in the local implementation of federal programs. Implementing such programs through national employees would significantly increase the size and intrusiveness of the national government. Moreover, local implementation may assure that these programs are implemented in ways that take local conditions into account.
For this reason, Congress has often avoided adoption of completely nationalized programs by one of two devices.
In the first, Congress creates a delivery system for federal programs in which the national government encourages local implementation of a federal program by providing significant matching funds. In this context, the phrase may be found in a number of Supreme Court and lower court federal cases. The most frequent early use of the phrase may be found in a series of cases describing the paradigm for federally sponsored welfare programs such as medical assistance or the former Aid to Families with Dependent Children (AFDC) programs in which a participating state's program is financed largely by the Federal Government, on a matching fund basis, subject to federal mandatory regulations.
The second method of encouraging states to implement federal programs is described in New York v. United States (1992). In this form, the Congress states that it will take over the regulation of an activity at the national level, unless the State itself implements its own program of regulation meeting minimum federal standards. Here, the motivation for State compliance is that absent state regulation, the state loses power over the regulated area entirely.