Circuit Judge:

Intake Water Company, a Delaware corporation, appeals a three-judge district court's grant of the Yellowstone River Compact Commission’s motion to dismiss for failure to state a claim. Fed.R.Civ.P. 12(b)(6). We have jurisdiction, 28 U.S.C. § 1291 , 1 and affirm.

I. BACKGROUND

The Yellowstone River Compact fixes the water usage of all waters of the Yellowstone River Basin. It was enacted by Congress on October 10, 1951. Act of Consent to the Yellowstone River Compact, 65 Stat. 663 , Ch. 629, Pub.L. 231 (1951). The signatory states, Montana, Wyoming and North Dakota, approved the Compact and codified it in their laws prior to congressional ratification. Mont.Code Ann. § 85-20-101 (1983); Wyo.Stat. § 41-12-607(e) (1977); N.D.Cent.Code § 61-23-01 (1960). The Yellowstone River Compact Commission is charged by Congress with implementation of the Compact.

In June, 1973, appellant Intake appropriated 80,650 acre feet per year of Yellowstone River water. Intake planned construction of a diversion works, including a reservoir near Dawson, Montana. Some of the water was to be diverted outside the Yellowstone Basin for use elsewhere in Montana and North Dakota and thus outside the jurisdiction of the Compact.

Intake challenged the validity of Article X of the Compact, contending that it discriminated against, unreasonably impeded and exerted an undue burden on the flow of interstate commerce in violation of the Commerce Clause of the Constitution. Art. I. § 8, cl. 3. Article X of the Compact restricts interbasin or interstate transfer of Yellowstone River waters, providing that:

II. STANDARD OF REVIEW

A ruling on a motion for failure to state a claim upon which relief can be granted is a ruling on a question of law, freely reviewable by the court of appeals. Rae v. Union Bank, 725 F.2d 478, 479 (9th Cir.1984). A motion to dismiss for failure to state a claim should not be granted unless it appears to a certainty that the plaintiff can prove no set of facts in support of his claim that would entitle him to relief. Id.

III. DISCUSSION

Intake alleges that Article X of the Compact, as state law, places a constitutionally impermissible burden on inter-state commerce by requiring unanimous consent of the signatory states for out-of-basin transfers of Yellowstone River water. Appellees, while not challenging the sufficiency of this argument, contend that: the Yellowstone River Compact was approved by Congress; because it was approved by Congress, it is federal, not state, law for pur *570 poses of Commerce Clause objections; therefore, the Compact cannot, by definition, be a state law impermissibly interfering with commerce but is instead a federal law, immune from attack.

The three-judge district court, in a well-reasoned decision, concluded that appellees' argument was the compelling one. Intake Water Co. v. Yellowstone River Compact Commission, 590 F.Supp. 293, 296-97 (1983). On the basis of that reasoning, we agree.

When Congress approved this compact, Congress was acting within its authority to immunize state law from some constitutional objections by converting it into federal law. Cuyler v. Adams, 449 U.S. 433, 438 , 101 S.Ct. 703, 706 , 66 L.Ed.2d 641 (1981). Accord, NYSA-ILA Vacation & Holiday Fund v. Waterfront Comm’n. New York Harbor, 732 F.2d 292 (2d Cir.), cert. denied, — U.S. —, 105 S.Ct. 175 , 83 L.Ed.2d 109 (1984). Nor can there be any question as to whether Congress in fact approved the state law from which immunity from Commerce Clause attack is claimed: The Compact was before Congress and Congress expressly approved it.

We find additional support for this holding in the Supreme Court’s recent decision of Northeast Bancorp Inc. v. Board of Governors of the Federal Reserve System, — U.S. —, 105 S.Ct. 2545 , 86 L.Ed.2d 112 (1985). There, the Court rejected the argument that regional limitations contained in Massachusetts and Connecticut statutes burdened interstate commerce. The Court held: “When Congress so chooses, state actions which it plainly authorizes are invulnerable to constitutional attack under the Commerce Clause.” 105 S.Ct. at 2554 . Thus, as a federal law, the Compact authorizes those actions included within its provisions.

Our review leads us to conclude that Intake failed, as a matter of law, to state any claim for which relief could be granted. The district court did not, therefore, err in granting the motion to dismiss and the portion of the district court’s judgment denying declaratory relief is

AFFIRMED.

. The explicit language of 28 U.S.C. § 1253 provides for direct appeal to the Supreme Court "from an order granting or denying ... an interlocutory or permanent injunction ...” and no such issue is presented here. Intake appeals only from that portion of the judgment denying its request for declaratory relief and expressly disclaims appeal from the district court’s denial of injunctive relief. We also note that the Supreme Court dismissed appellant Intake’s direct appeal for lack of jurisdiction. Intake Water Co. v. Yellowstone River Compact Commission, — U.S. —, 105 S.Ct. 316 , 83 L.Ed.2d 254 (1984).