Ratchet Theory Law and Legal Definition

Ratchet theory is a principle of constitutional law that Congress may enact laws that strengthen guarantees under the Due Process and Equal Protection Clauses of the Fourteenth Amendment, as interpreted by the Supreme Court, but may not dilute those guarantees. The theory was stated by Justice Brennan in Katzenbach v. Morgan, 384 U.S. 641, 653-56, 16 L. Ed. 2d 828, 86 S. Ct. 1717 (1966), which maintained that Congress could expand the substantive rights contained in § 1 of the Fourteenth Amendment even when the courts had explicitly refused to recognize the existence of such rights. However, this theory was later rejected by the Supreme Court in City of Boerne v. Flores, 521 U.S. 507 (1997) where it held that “Congress does not enforce a constitutional right by changing what the right is. It has been given the power 'to enforce,' not the power to determine what constitutes a constitutional violation.”

Ratchet theory is also known as one-way ratchet theory as the enabling clause works in only one direction, like a ratchet.