Since its enactment in 1948, the Military Selective Service Act (MSSA) has required men, but not women, to register for a potential military draft. The MSSA previously withstood constitutional review when, in 1981, the U.S. Supreme Court upheld the statute’s sex-based classification under the rationale that the purpose of the MSSA was to raise combat troops in the event of a military crisis. Because women were not allowed to participate in combat, the Court held that the statute did not need to extend the registration requirement to women. In 2013, however, the Department of Defense eliminated all combat restrictions on women. With that policy change, the rationale for the Supreme Court’s earlier decision collapsed. Since the change allowing women to participate in combat, the MSSA has come under renewed scrutiny, with a 2019 federal district court decision holding that the statute violates the Fifth Amendment’s Due Process Clause. That decision was subsequently reversed by the U.S. Court of Appeals for the Fifth Circuit, but the Fifth Circuit declined to consider the merits of the district court decision and, instead, based its reversal solely on the rationale that only the Supreme Court may reverse itself. In addition, a blue-ribbon commission established by the U.S. Congress recommended in 2020 that lawmakers amend the MSSA to extend the registration requirement to women. This Article provides background relating to the current controversy over whether to amend the MSSA to require women to register for the draft. It argues that the existing sex-based classification in the statute fails to advance the MSSA’s purposes. Moreover, the sex-based classification relies on archaic generalizations about the role of women, is a detriment to America’s national security,and undermines sex equality. The Article contends that the MSSA violates the Fifth Amendment and should be amended by Congress.