What are concurrent powers?

Concurrent powers are the powers that both the federal government and the state governments may exercise at the same time over the same people and territory. Unlike enumerated federal powers and reserved state powers, concurrent powers are shared, with each level acting within its own constitutional sphere. The most important concurrent powers include the power to tax, the power to borrow money, the power to spend, the power to make and enforce laws, the power to establish courts, the power to charter corporations, the power to take private property for public use under eminent domain with just compensation, and the power to regulate elections within constitutional limits.

Both federal and state governments collect income, sales, property, and other taxes, although on different bases and for different purposes. Both run prison systems, criminal courts, and law enforcement agencies. Both build roads, fund schools, and operate public health programs. Both hold elections and license activities.

Concurrent power is what allows a single act to be a federal crime and a state crime at the same time, like bank robbery or drug trafficking, with separate prosecutions possible without violating the Double Jeopardy Clause under the dual sovereignty doctrine confirmed by the Supreme Court in Gamble v. United States in 2019.

The doctrine of preemption resolves conflicts when concurrent action collides. Under the Supremacy Clause of Article VI, when federal law and state law conflict in a way that cannot be reconciled, federal law wins. Express preemption occurs when Congress states explicitly that federal law displaces state law, for example in the federal regulation of nuclear power or aircraft safety. Implied preemption occurs when federal regulation is so comprehensive that no room is left for state action, when state law obstructs the purposes of federal law, or when compliance with both is impossible.

Many federal-state programs are designed to be cooperative rather than competitive. Medicaid, unemployment insurance, the Clean Air Act, and the Clean Water Act all share authority and funding between Washington and the states, with federal standards setting a floor that states may exceed. Concurrent powers make day-to-day American government more layered than a strict separation of powers would allow.