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:
BROOKS v. MISSOURI PACIFIC RAILROAD CO.
No. 53.
Argued January 7-8, 1964.
Decided February 17, 1964.
Philip B. Heymann argued the cause for petitioner. On the brief were Solicitor General Cox, Assistant Attorney General Douglas, Alan S. Rosenthal and Richard S. Salzman.
Robert V. Light argued the cause for respondent. With him on the brief were Herschel H. Friday and W. J. Smith.
Clarence M. Mulholland, Edward J. Hickey, Jr. and Richard R. Lyman filed a brief for the Railway Employes’ Department, AFL-CIO, as amicus curiae, urging affirmance.
Mr. Justice Goldberg
delivered the opinion of the Court.
This case differs only slightly from Tilton v. Missouri Pac. R. Co. decided today. Ante, at 169. Petitioner here was hired by the railroad on July 5, 1951, to serve as an apprentice machinist in Monroe, Louisiana. After completing seven months of apprenticeship, he was drafted into military service. He was honorably discharged on November 7, 1953, and immediately returned to work as an apprentice in Monroe. On April 29, 1954, petitioner was laid off because of the termination of the apprenticeship program at Monroe. On July 6, 1954, he resumed his apprenticeship with the railroad in St. Louis, Missouri. On July 25, 1955, at his request and with the railroad’s approval, petitioner was transferred to the railroad’s shops in North Little Rock, Arkansas, where he completed his apprenticeship on January 23, 1958. He was immediately employed at the North Little Rock shops as a journeyman machinist and assigned a seniority rating as of that date and location.
Petitioner sought a North Little Rock seniority date of November 3, 1955. He claimed that but for his military service, he would have completed his apprenticeship on that date and at that location. The railroad offered him that seniority date, but only at the Monroe location. Petitioner declined this offer on the ground that there were no employment opportunities at that location.
Petitioner brought suit in the District Court for the Eastern District of Arkansas. The court found, on the basis of adequate evidence, that “in practice . . . discretion had no play .... [Transition from the rank of apprentice to the rank of mechanic was automatic.” It also found that “in no event would plaintiff have completed his apprenticeship at Monroe.” But for his military service he “would have completed [his training] in 1955 . . . and ... as of that time he was employed in the North Little Rock shops and would have been hired there automatically as a journeyman mechanic. Had he been so employed at that time, his seniority point would have been fixed at North Little Rock under the actual practice of the railroad and the Union in connection with the initial employment of mechanics.” Accordingly, the District Court directed the railroad to grant him seniority as of November 3, 1955, at North Little Rock.
The Court of Appeals for the Eighth Circuit reversed, 308 F. 2d 531, on the basis of its earlier decision in Tilton v. Missouri Pac. R. Co., 306 F. 2d 870. The court held that the advancement from apprentice to journeyman lacked the predictable certainty required by the Tilton decision, because “[t]he balance between supply and demand of a particular category of workmen at a designated point at a future date cannot be foreseen or predicted with any degree of certainty.” 308 F. 2d, at 533. We granted certiorari, 372 U. S. 904.
We reverse the judgment of the Court of Appeals for the reasons stated in Tilton, ante, at 169. As we said in that case:
“In every veteran seniority case the possibility exists that work of the particular type might not have been available; that the veteran would not have worked satisfactorily during the period of his absence; that he might not have elected to accept the higher position; or that sickness might have prevented him from continuing his employment. In light of the purpose and history of this statute, however, we cannot assume that Congress intended possibilities of this sort to defeat the veteran’s seniority rights.” Ante, at 180-181.
We think that the foregoing analysis is dispositive of the problem here. The possibility that the “balance between supply and demand” would have prevented petitioner’s otherwise automatic promotion should not defeat his seniority claim. This possibility, like the possibilities discussed in Tilton, always exists.
We accept the conclusion of the District Court that but for petitioner’s military service, he probably would have achieved, by virtue of continued satisfactory employment, seniority status as a journeyman mechanic in North Little Rock on November 3, 1955. It follows, therefore, that he is entitled to this status under the relevant statutes. The judgment of the Court of Appeals is reversed and the cause remanded for proceedings in conformity with this opinion.
Reversed and remanded.
The opinion of the District Court is not reported.

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