The power of congress to enact laws by which the national government assumes complete or partial responsibility for a state government function is known as "Preemption".
The intensity of Congress to establish laws by which the national government accept complete or partial responsibility for a state government work is called preemption. At the point when the national government bears another administration work, it confines the optional intensity of the states. Congressional prohibition of state or nearby tax assessment of the Internet is a case of complete preemption.
Preemption is an advanced power. Congress passed just twenty-nine preemptive acts previously 1900.