Title 42 U.S.C. § 1437d(l)(6) provides that each 'public housing agency shall utilize leases . . . providing that . . . any drug-related criminal activity on or off [federally assisted low-income housing] premises, engaged in by a public housing tenant, any member of the tenant's household, or any guest or other person under the tenant's control, shall be cause for termination of tenancy.' Rucker (Ps) are four public housing tenants of the Oakland Housing Authority (OHA) (D). The leases that Ps signed obligate the tenants to 'assure that the tenant, any member of the household, a guest, or another person under the tenant's control, shall not engage in . . . any drug-related criminal activity on or near the premises.' OHA instituted eviction proceedings against Ps alleging violations of this lease provision. Ps sued OHA and HUD (D) disputing their interpretation of §1437(d)(l) of the Anti-Drug Abuse Act of 1988 (ADAA). Ps claimed that ADAA was unconstitutional. D's regulations administering § 1437d(l)(6) require lease terms authorizing evictions in these circumstances. D's regulations provide that the public housing authority shall have discretion to consider all of the circumstances of the case and includes those situations in which 'the tenant did not know, could not foresee, or could not control behavior by other occupants of the unit.” The District Court issued a preliminary injunction, enjoining OHA from terminating the leases of tenants for drug-related criminal activity that does not occur within the tenant's apartment unit when the tenant did not know of and had no reason to know of, the drug-related criminal activity. A panel of the Court of Appeals reversed holding that § 1437d(l)(6) unambiguously permits the eviction of tenants who violate the lease provision, regardless of whether the tenant was personally aware of the drug activity, and that the statute is constitutional. An en banc panel of the Court of Appeals reversed and affirmed the District Court's grant of the preliminary injunction. It held that the eviction of innocent tenants was inconsistent with Congressional intent and must be rejected' under the first step of Chevron. The Supreme Court granted certiorari.