The Civil Rights Cases, 109 U. S. 3 (1883), "embedded in our constitutional law" the principle "that the action inhibited by the first section [Equal Protection Clause] of the Fourteenth Amendment is only such action as may fairly be said to be that of the States. That Amendment erects no shield against merely private conduct, however discriminatory or wrongful." Chief Justice Vinson, in Shelley v. Kraemer, 334 U. S. 1, 334 U. S. 13 (1948). It was language in the opinion in the Civil Rights Cases, supra, that phrased the broad test of state responsibility under the Fourteenth Amendment, predicting its consequence upon "state action of every kind . . . which denies . . .the equal protection of the laws." At p. 109 U. S. 11. And only two Terms ago, some 75 years later, the same concept of state responsibility was interpreted as necessarily following upon "state participation through any arrangement, management, funds or property." Cooper v. Aaron, 358 U. S. 1, 358 U. S. 4 (1958). It is clear, as it always has been since the Civil Rights Cases, supra, that "Individual invasion of individual rights is not the subject matter of the amendment," 109 U.S. at 109 U. S. 11, and that private conduct abridging individual rights does no violence to the Equal Protection Clause unless, to some significant extent, the State, in any of its manifestations, has been found to have become involved in it. Because the virtue of the right to equal protection of the laws could lie only in the breadth of its application, its constitutional assurance was reserved in terms whose imprecision was necessary if the right were to be enjoyed in the variety of individual-state relationships which the Amendment was designed to embrace. For the same reason, to fashion and apply a precise formula for recognition of state responsibility under the Equal Protection Clause is an "impossible task" which "This Court has never attempted." Kotch v. Board of River Port Pilot Comm'rs, 330 U. S. 552, 330 U. S. 556. Only by sifting facts and weighing circumstances can the nonobvious involvement of the State in private conduct be attributed its true significance.
Burton v. Wilmington Parking Authority, 365 US 715 (1961).