The separate opinion referred to was delivered December 4, 1939 (see footnote, p. 4), and is as follows:
Mr. Chief Justice Hughes:I concur in the reversal of the judgment upon the ground that Wilson & Co., a Delaware corporation, was not amenable to suit in the federal District Court in Oklahoma. The question is essentially the same as that presented in Neirbo Co. v. Bethlehem Shipbuilding Corp., 308 U. S. 165, and what was said in the dissenting opinion in that case need not be repeated here. (See, as to the scope of the consent under the Oklahoma statute, the *10observations of the Circuit Court of Appeals in the Neirbo case, 103 F. 2d 765, 769.)
But if it be granted that the Delaware Corporation was amenable to the process in question, I am unable to agree that the complainants should be denied relief because of the defense of res judicata. The judgment to which this effect is given was rendered by the Supreme Court of Oklahoma in 1930, sustaining, on appeal, an order of the Corporation Commission requiring gas to be furnished to Wilson & Co. at a specified rate. Oklahoma Gas & Electric Co. v. Wilson & Co., 146 Okla. 272; 288 P. 316. At the time of that decision, the review by the Supreme Court of Oklahoma of such an order of the Corporation Commission was considered to be legislative in character. Oklahoma Gas Co. v. Russell, 261 U. S. 290, 291; McAlester Gas & Coke Co. v. Corporation Commission, 101 Okla. 268, 270; 224 P. 698; City of Poteau v. American Indian Oil & Gas Co., 159 Okla. 240, 242, 243; 18 P. 2d 523, in which the state court cited with approval the decision to that effect of the Circuit Court of Appeals in Oklahoma Gas & Electric Co. v. Wilson & Co., 54 F. 2d 596, 598, 599, applying the Oklahoma decisions. Compare Oklahoma Gas & Electric Co. v. Oklahoma Packing Co., 292 U. S. 386, 388; Corporation Commission v. Cary, 296 U. S. 452, 458. The contention of the complainants before the state court was that, the Commission’s order violated their rights under the Federal Constitution. 146 Okla. 272, 281, 288; 288 P. 316. But in the view, as then held, that the action of the state court was legislative in character, no appeal lay to this Court from the state court’s determination of the federal question. Prentis v. Atlantic Coast Line Co., 211 U. S. 210, 226, 227; Oklahoma Gas Co. v. Russell, supra. Accordingly, the complainants brought this suit in the federal court to enjoin the enforcement of the Commission’s order.
*11It was not until several years later (in 1935) that the Oklahoma Supreme Court decided, in a suit between other parties, that its action in reviewing such an order of the Commission was judicial and not legislative in character. Oklahoma Cotton Ginners’ Assn. v. State, 174 Okla. 243; 51 P. 2d 327. The manifest injustice of holding that complainants are bound by the state court’s ruling in 1930 as a judicial determination, when at that time under the state court’s construction of the state constitution the complainants were not at liberty to treat the ruling as á judicial determination and to obtain a review of the federal question by this Court upon that ground, is not met, as it seems to me, by invoking the general doctrine of res judicata.
Whether the judgment of a state court is res judicata is a question of state law. The federal courts are not bound to give such domestic judgments any greater force than that awarded them by the courts of the State where rendered. Union & Planters’ Bank v. Memphis, 189 U. S. 71, 75; Covington v. First National Bank, 198 U. S. 100, 109; Wright v. Georgia Railroad & Banking Co., 216 U. S. 420, 429. I think that we are not at liberty to assume that the Oklahoma court would so far depart from the plain requirements of justice as to preclude in these circumstances a review of the federal question in a court of competent jurisdiction. The state court has not spoken to that effect and what the state court has said I think clearly imports the contrary.
This appears from its decision in Oklahoma Gas & Electric Co. v. Wilson & Co., 178 Okla. 604; 63 P. 2d 703. That was an action in the state court on the supersedeas bond given on the appeal to the Supreme Court from the Commission’s order in question, and Wilson & Co., the plaintiff, had judgment. The Supreme Court reversed that judgment and directed a stay pending the deter*12mination in this very suit in the federal court of the validity of the Commission’s order. The Supreme Court expressly referred to its decision, in 1935, in Oklahoma Cotton Ginners’ Assn. v. State, supra, that its action in reviewing orders of the Commission affecting rates of public utilities constituted a judicial determination of the questions involved. But instead of holding that the ruling in 1930, upon the order now under review, constituted a final adjudication of the validity of that order, the Supreme. Court held that the question of validity was an open one for determination by the federal court in the present suit. After saying that in view of the uncertainty with respect to the “right to a judicial remedy in the state courts,” the federal court had acquired jurisdiction of this suit, the state court concluded as follows:
“That remedy was available to them as the only certain method of obtaining a judicial determination of the validity of the commission’s order. The suit was a direct attack upon such order, and until its validity was established in that suit, the state court was without jurisdiction to proceed with an action based upon such order. This for the reason that where direct attack in equity is made upon the order of the commission, the defendants’ liability on such order is not finally determined judicially until final determination of the equitable action.”
If under the state law as thus declared in Oklahoma upon consideration of the particular circumstances of this case, liability on the Commission’s order is not finally determined judicially until the determination of that question in this equity suit, I am at a loss to understand how the action of the state court on the 1930 appeal can be regarded as res judicata and thus a bar to that determination.
The decree below enjoining enforcement of the Commission’s order, appropriately followed the determination of its invalidity. The point that the decree should not *13have gone further and enjoined the prosecution of the action in the state court upon the supersedeas bond is at best only one of technical importance, as the state court itself enjoined such proceedings pending the determination of this suit, apparently in the view that a determination herein of the invalidity of the order would dispose of the merits.
Mr. Justice McReynolds and Mr. Justice Roberts join in this opinion.