The Oakland Housing Authority (OHA) required public-housing tenants to agree to lease terms that made a tenant subject to eviction if any member of the tenant’s household engaged in drug-related criminal activity. These lease terms were required by the Anti-Drug Abuse Act of 1988 (ADAA), 42 U.S.C. §1437(d)(l)(6), which sought to decrease the threat that drug dealers posed to low-income housing residents. The OHA instituted eviction proceedings in state court against Pearlie Rucker and three other public-housing tenants (plaintiffs) whose household members had engaged in drug crimes. The plaintiffs brought suit against the OHA and the Department of Housing and Urban Development (HUD) (defendant) in federal district court, challenging HUD’s interpretation of the ADAA and claiming that the ADAA was unconstitutional. HUD’s implementing regulations provided that (1) local public-housing authorities had discretion over whether tenants would be evicted, and (2) this discretion included a consideration of whether the tenant knew or should have known about the household member’s drug-related activities. The district court issued a preliminary injunction in favor of the plaintiffs. An en banc panel of the court of appeals affirmed. The United States Supreme Court granted certiorari to consider whether the ADAA required lease terms permitting local public-housing authorities to evict tenants who had no knowledge of drug activity.