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:
BALTIMORE & OHIO RAILROAD CO. et al. v. BOSTON & MAINE RAILROAD et al.
No. 97.
Argued March 27, 1963.
Decided May 20, 1963
Robert W. Oinnane, Jervis Langdon, Jr., and William L. Marbury argued the cause for appellants. With Mr. Ginnane on the briefs for the Interstate Commerce Commission, appellant in No. 99, was I. K. Hay. With Mr. Langdon on the briefs for appellants in No. 97 were Richard R. Bongarts, Robert B. Claytor, John W. Hanifin, John Henry Lewin and William C. Purnell. With Mr. Marbury on the briefs for appellants in No. 98 were Chas. R. Seal, J. Cookman Boyd, Jr., Donald Macleay, John Martin Jones, Jr., Morris Duane, Warren Price, Jr., William C. Burt and Robert M. Beckman.
J. William Doolittle, Thomas E. Dewey and Robert G. Bleakney, Jr. argued the cause for appellees. On the brief for the Boston &'Maine Railroad et al. were Robert G. Bleakney, Jr., Hénry E. Foley and Neal Holland. On the brief for the United States were Solicitor General Cox, Assistant Attorney-General Loevinger, Stephen J. Poliak, Robert B. Hummel, Irwin A. Seibel and John H. D. Wigger. On the brief for the New York Central Railroad Company et al. were Thomas E. Dewey, Everett I. Willis and Leo B. Connelly. On the brief for the State of New York et al. were Louis J. Lejkowitz, Attorney-General of New York, Paxton Blair, Solicitor General, Dunton F. Tynan, Assistant Solicitor General, Sidney Goldstein, Leo A. Larkin, F. A. Mulhern, Morris Handel, Samuel Mandell, Charles W. Merritt, Walter J. Myskow-ski, Arthur L. Winn, Jr. and Samuel H. Moerman.
Together with. No. 98, Maryland Port Authority et al. v. Boston & Maine Railroad et al., and No. 99, Interstate Commerce Commission v. Boston & Maine Railroad et al., also on appeals from the same Court.
Per Curiam.
The judgment is affirmed by an equally divided Court.
Mr. Justice White 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: 2