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:
ARSENAULT v. MASSACHUSETTS.
No. 187,
Mise.
Decided October 14, 1968.
F. Lee Bailey for petitioner.
Elliot L. Richardson, Attorney General of Massachusetts, Howard M. Miller, Assistant Attorney General, and Richard L. Levine, Deputy Assistant Attorney General, for respondent.
Per Curiam.
In February 1955 petitioner was arrested in connection with a recent homicide and attempted robbery. The next morning at a probable-cause hearing, but unassisted by counsel, he pleaded guilty to counts of murder and assault with intent to rob. Six days later at his arraignment, and again unaided by counsel, he pleaded not guilty to an indictment charging him with first-degree murder. After being assigned counsel for trial he took the stand in his own defense and again pleaded not guilty to the indictment, asserting instead that he lacked the premeditation necessary for first-degree murder. On cross-examination, the district attorney questioned him about his prior statements at the preliminary hearing and introduced his plea of guilty for the purpose of refreshing his memory. The jury then returned a verdict of guilty and imposed a sentence of death, since commuted to life imprisonment. On direct review by the Massachusetts Supreme Judicial Court, he assigned as error the admission at trial of his prior plea. The court rejected his claim by affirming the conviction.
In 1966 petitioner sought post-conviction relief from the Massachusetts Supreme Judicial Court on the ground that our supervening decision in White v. Maryland, 373 U. S. 59, rendered his conviction void. While recognizing a “close similarity” between his case and White, that court nonetheless reaffirmed the judgment below on the ground that White was not retroactive. Petitioner comes here by petition for a writ- of certiorari. The motion for leave to proceed in forma pauperis and the petition for a writ of certiorari are granted.
In White v. Maryland an accused pleaded guilty when arraigned at a preliminary hearing, and at that time had no counsel to represent him. We held that Hamilton v. Alabama, 368 U. S. 52, was applicable, as only the aid of counsel could have enabled the accused to know all the defenses available to him and to plead intelligently. White v. Maryland is indistinguishable in principle from the present case; and we hold that it is applicable here although it was not decided until after the arraignment and trial in the instant case.
The right to counsel at the trial (Gideon v. Wainwright, 372 U. S. 335); on appeal (Douglas v. California, 372 U. S. 353); and at the other “critical” stages of the criminal proceedings (Hamilton v. Alabama, supra) have all been made retroactive, since the “denial of the right must almost invariably deny a fair trial.” See Stovall v. Denno, 388 U. S. 293, 297.
Reversed.
For the distinction drawn between the right-to-counsel cases and those arising under the Fourth and Fifth Amendments, see also Tehan v. Shott, 382 U. S. 406, 416.

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