Cite as: 601 U. S. ____ (2024) 9 Opinion of the Court up for a lack of state authority at the first. A The first prong of this test is grounded in the bedrock requirement that “the conduct allegedly causing the deprivation of a federal right be fairly attributable to the State.” Lugar, 457 U. S., at 937 (emphasis added). An act is not attributable to a State unless it is traceable to the State’s power or authority. Private action—no matter how “official” it looks—lacks the necessary lineage. This rule runs through our cases. Griffin stresses that the security guard was “possessed of state authority” and “purport[ed] to act under that authority.” 378 U. S., at 135. West v. Atkins states that the “traditional definition” of state action “requires that the defendant . . . have exercised power ‘possessed by virtue of state law and made possible only because the wrongdoer is clothed with the authority of state law.’ ” 487 U. S. 42, 49 (1988) (quoting United States v. Classic, 313 U. S. 299, 326 (1941)). Lugar emphasizes that state action exists only when “the claimed deprivation has resulted from the exercise of a right or privilege having its source in state authority.” 457 U. S., at 939; see also, e.g., Edmonson v. Leesville Concrete Co., 500 U. S. 614, 620 (1991) (describing state action as the “exercise of a right or privilege having its source in state authority”); Screws, 325 U. S., at 111 (plurality opinion) (police-officer defendants “were authorized to make an arrest and to take such steps as were necessary to make the arrest effective”). By contrast, when the challenged conduct “entail[s] functions and obligations in no way dependent on state authority,” state action does not exist. Polk County v. Dodson, 454 U. S. 312, 318–319 (1981) (no state action because criminal defense “is essentially a private function . . . for which state office and authority are not needed”); see also Jackson v. Metropolitan Edison Co., 419 U. S. 345, 358–359 (1974). Lindke’s focus on appearance skips over this crucial step.