opinion: MASSACHUSETTS MUTUAL LIFE INSURANCE CO. v. LUDWIG, ADMINISTRATOR
  No. 75-1504.
  Decided June 14, 1976
  Per Curiam.
  This is a diversity case. Petitioner (the insurer) issued a life insurance policy in Michigan to Dean E. Cane providing for double indemnity if Cane's “death was the result of an injury sustained while the insured was a passenger in or upon a public conveyance then being operated by a common carrier to transport passengers for hire ....'' Cane was killed in Illinois by a freight train while crossing a railroad track in order to board a commuter train which had not yet arrived at the station. The insurer paid Cane's estate ordinary benefits, but denied liability under the double indemnity provision of the policy.
  The administrator of Cane’s estate (respondent) sued the insurer in the District Court for the Northern District of Illinois to recover benefits under the double indemnity provision. The District Court held that under Illinois conflict-of-laws rules, the law of the situs of the contract (Michigan) applied, and that under Michigan law the insurer was liable only for ordinary benefits. The administrator appealed. The insurer argued in the Court of Appeals for the Seventh Circuit that the District Court’s application and interpretation of Michigan law was correct, and alternatively that Illinois conflict-of-laws rules required application of Illinois— not Michigan — substantive law in this case, and that under Illinois substantive law its liability was also only for ordinary benefits. The Court of Appeals reversed, 524 F. 2d 376 (1975), but without reaching the question of which State’s substantive law would be applicable under the Illinois conflicts rule. The court held that the insurer was precluded from arguing on appeal the applicability of Illinois substantive law, because it had not cross-appealed from the District Court’s ruling that Michigan law applied. Id., at 379 n. 1.
  The Court of Appeals’ decision on this issue is plainly at odds with the “inveterate and certain” rule, Morley Co. v. Maryland Cas. Co., 300 U. S. 185, 191 (1937), of United States v. American Ry. Exp. Co., 265 U. S. 425, 435 (1924), where a unanimous Court said:
  “It is true that a party who does not appeal from a final decree of the trial court cannot be. heard in opposition thereto when the case is brought here by the appeal of the adverse party. In other words, the appellee may not attack the decree with a view either to enlarging his own rights thereunder or of lessening the rights of his adversary, whether what he seeks is to correct an error or to supplement the decree with respect to a matter not dealt with below. But it is likewise settled that the appellee may, without taking a cross-appeal, urge in support of a decree any matter appearing in the record, although his argument may involve an attack upon, the reasoning of the lower court or an insistence upon matter overlooked or ignored by it.” (Footnote omitted.)
  The argument of the insurer before the Court of Appeals that Illinois, not Michigan, substantive law applied was no more than “an attack upon the reasoning of the lower court,” and as such required no cross-appeal.
  Because the Court of Appeals did “not reach the issue nor express any opinion on the effect of the tort claim conflicts of law doctrine” of Illinois, 524 F. 2d, at 379 n. 1, we think it “appropriate to remand the case rather than deal with the merits of that question in this Court.” Dandridge v. Williams, 397 U. S. 471, 476 n. 6 (1970). Accordingly, the petition for writ of certiorari is granted, the judgment of the Court of Appeals is vacated, and the case is remanded for further proceedings in conformity with this opinion.
  So ordered.
  Mr. Justice Stevens took no part in the consideration or decision of this case.
instruction: 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.