What follows is an opinion from the Supreme Court of the United States. Your task is to determine the bases on which the Supreme Court rested its decision with regard to the legal provision that the Court considered in the case. Consider "judicial review (national level)" if the majority determined the constitutionality of some action taken by some unit or official of the federal government, including an interstate compact. Consider "judicial review (state level)" if the majority determined the constitutionality of some action taken by some unit or official of a state or local government. Consider "statutory construction" for cases where the majority interpret a federal statute, treaty, or court rule; if the Court interprets a federal statute governing the powers or jurisdiction of a federal court; if the Court construes a state law as incompatible with a federal law; or if an administrative official interprets a federal statute. Do not consider "statutory construction" where an administrative agency or official acts "pursuant to" a statute, unless the Court interprets the statute to determine if administrative action is proper. Consider "interpretation of administrative regulation or rule, or executive order" if the majority treats federal administrative action in arriving at its decision.Consider "diversity jurisdiction" if the majority said in approximately so many words that under its diversity jurisdiction it is interpreting state law. Consider "federal common law" if the majority indicate that it used a judge-made "doctrine" or "rule; if the Court without more merely specifies the disposition the Court has made of the case and cites one or more of its own previously decided cases unless the citation is qualified by the word "see."; if the case concerns admiralty or maritime law, or some other aspect of the law of nations other than a treaty; if the case concerns the retroactive application of a constitutional provision or a previous decision of the Court; if the case concerns an exclusionary rule, the harmless error rule (though not the statute), the abstention doctrine, comity, res judicata, or collateral estoppel; or if the case concerns a "rule" or "doctrine" that is not specified as related to or connected with a constitutional or statutory provision. Consider "Supreme Court supervision of lower federal or state courts or original jurisdiction" otherwise (i.e., the residual code); for issues pertaining to non-statutorily based Judicial Power topics; for cases arising under the Court's original jurisdiction; in cases in which the Court denied or dismissed the petition for review or where the decision of a lower court is affirmed by a tie vote; or in workers' compensation litigation involving statutory interpretation and, in addition, a discussion of jury determination and/or the sufficiency of the evidence.

Opinion:
ORDER OF RAILWAY CONDUCTORS OF AMERICA v. SOUTHERN RAILWAY CO.
No. 438.
Argued February 8-9, 1950. —
Decided April 10, 1950.
V. C. Shuttleworth argued the cause for petitioner. With him on the brief were Harry E. Wilmarth and Frederick H. Horlbeck.
W. S. Macgill argued the cause for respondent. With him on the brief were Nath B. Barnwell, Frank G. Tompkins, Henry L. Walker and Sidney S. Alderman.
Mr. Justice Black
delivered the opinion of the Court.
This case raises the same statutory question as Slocum v. Delaware, L. & W. R. Co., ante, p. 239, The petitioner, Order of Railway Conductors, is the only accredited bargaining representative of conductors employed by the respondent Southern Railway. A dispute arose between certain conductors and the railroad concerning the railroad’s obligation under the collective-bargaining agreement to give conductors extra pay for certain services. The claims of the conductors were referred to the union, which sought by negotiation to persuade the railroad to pay. The railroad refused, and thereafter prayed a South Carolina state court for a declaratory judgment interpreting the agreement as not requiring the claimed payments. The trial court first refused to exercise jurisdiction. Citing Order of Conductors v. Pitney, 326 U. S. 561, it held that state courts, like federal courts, should leave settlement of such disputes to the National Railroad Adjustment Board. The State Supreme Court reversed, holding that the state court did have power to interpret the bargaining agreement and adjudicate the dispute. 210 S. C. 121, 41 S. E. 2d 774. After a lengthy trial the lower court held that the collective agreement did not require the compensation sought by the conductors and entered the declaratory judgment requested. The Supreme Court affirmed. 215 S. C. 280, 54 S. E. 2d 816.
For reasons set out in the Slocum case, ante, p. 239, we hold that the South Carolina state court was without power to interpret the terms of this agreement and adjudicate the dispute. We discuss this case separately because it sharply points up the conflicts that could arise from state court intervention in railroad-union disputes. After the railroad had sued in the state court, the union filed a petition for hearing and award before the Adjustment Board. The state court nevertheless proceeded to adjudicate the dispute. Sustaining the state court’s action would invite races of diligence whenever a carrier or union preferred one forum to the other. And if a carrier or a union could choose a court instead of the Board, the other party would be deprived of the privilege conferred by § 3 First (i) of the Railway Labor Act, 48 Stat. 1191, 45 U. S. C. § 153 First (i), which provides that after negotiations have failed “either party” may refer the dispute to the appropriate division of the Adjustment Board.
The judgment of the South Carolina Supreme Court is reversed, and the cause is remanded for proceedings not inconsistent with this opinion.
It is so ordered.
Mr. Justice Reed is of the view that the decision below should be affirmed for the reasons set out in his dissent in Slocum v. Delaware, L. & W. R. Co., ante, p. 245.
Mr. Justice Douglas took no part in the consideration or decision of this case.

Question: What is the basis of the Supreme Court's decision?

Choices:
judicial review (national level)
judicial review (state level)
Supreme Court supervision of lower federal or state courts or original jurisdiction
statutory construction
interpretation of administrative regulation or rule, or executive order
diversity jurisdiction
federal common law

Answer: 3