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:
BLAU v. UNITED STATES.
No. 21.
Argued November 7, 1950.
Decided January 15, 1951.
Samuel D. Menin argued the cause and filed a brief for petitioner.
Solicitor General Perlman argued the cause for the United States. With him on the brief were Assistant Attorney General Mclnerney, John F. Davis and J. F. Bishop.
Mr. Justice Black
delivered the opinion of the Court.
Petitioner was summoned to appear before a federal district grand jury in Denver, Colorado. Both before that body and before the district judge where he was later taken, petitioner declined to answer questions concerning the activities and records of the Communist Party of Colorado, claiming his constitutional privilege against self-incrimination. He also refused to reveal the whereabouts of his wife, who was wanted by the grand jury as a witness in connection with the same investigation. As to this refusal to testify, petitioner asserted his privilege against disclosing confidential communications between husband and wife. The district judge overruled both claims of privilege and sentenced petitioner to six months in prison for contempt of court. The Court of Appeals for the Tenth Circuit affirmed. 179 F. 2d 559.
For the reasons set out in our recent opinion in Patricia Blau v. United States, 340 U. S. 159, we hold it was error to fail to sustain the claim of privilege against self-incrimination.
This leaves for consideration the validity of the sentence insofar as it rests on the failure of petitioner to disclose the whereabouts of his wife. In Wolfle v. United States, 291 U. S. 7, this Court recognized that a confidential communication between husband and wife was privileged. It is not disputed in the present case that petitioner obtained his knowledge as to where his wife was by communication from her. Nevertheless, the Government insists that he should be denied the benefit of the privilege because he failed to prove that the information was privately conveyed. This contention ignores the rule that marital communications are presumptively confidential. Wolfle v. United States, supra, at 14; Wigmore, Evidence, § 2336. The Government made no effort to overcome the presumption. In this case, moreover, the communication to petitioner was of the kind likely to be confidential. Petitioner’s wife, according to the district judge, knew that she and a number of others were “wanted” as witnesses by the grand jury but she “hid out, apparently so that the process . . . could not be served upon her.” Several of the witnesses who appeared were put in jail for contempt of court. Under such circumstances, it seems highly probable that Mrs. Blau secretly told her husband where she could be found. Petitioner’s refusal to betray his wife’s trust therefore was both understandable and lawful. We have no doubt that he was entitled to claim his privilege.
Reversed.
Me. Justice Clark took no part in the consideration or decision of this case.
Petitioner’s wife, when apprehended, was sentenced to one year’s imprisonment for contempt, Patricia Blau v. United States, supra, although other witnesses who refused to testify received shorter sentences. In sentencing Mrs. Blau, the judge stated: “I haven’t much sympathy for this lady because, as I said, she defied the Court by avoiding the process of the Court when she knew very well that she was wanted here, and yet she hid out, apparently so that the process of this court could not be served upon her.”
In view of our decision on this phase of the case, it is unnecessary to reach the question whether the single conviction for contempt (which was based on the refusal to give incriminating testimony and on the refusal to reveal a confidential marital communication) would be valid if petitioner were entitled to claim one, but not both, of the privileges.

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: 6
2