delivered the opinion of the Court.
The Commonwealth of Pennsylvania holds the petitioner prisoner under a life sentence as an habitual criminal. His claim here, protesting denial by the State Supreme Court of his petition for a writ of habeas corpus, is that the Federal Constitution requires Pennsylvania to release him on due process of law grounds because (1) he was sentenced as a fourth offender without counsel or offer of counsel; (2) one of the convictions on which the sentence is based occurred before the enactment of the Pennsylvania Habitual Criminal Act1 and the statute is therefore unconstitutionally retroactive and ex post jacto; and (3) sentencing under this Act unconstitutionally subjects him to double jeopardy.
At the outset, we face the suggestion that the ease cannot properly be decided on the merits by this Court because, as a matter of state law, the attack on the life sentence may be premature since petitioner would be validly restrained on prior sentences not expiring until at least February 1949, even if the life sentence were to be invalidated. Some members of the Court prefer to affirm the judgment on that ground. However, since the state law question is not free from difficulty, the issue was not fully litigated in this Court, and since, on the merits,2 the same conclusion is reached, we dispose of the case in that manner.
*730Beginning in 1927, at the age of seventeen, this petitioner has been arrested eight times for crimes of violence, followed in each instance by plea of guilty or by conviction. Respondent states, and petitioner does not deny, that of the last 20 years of his life, over 13 years have been spent in jail. A schedule of his pleas or convictions and pertinent data is appended, post, p. 732, those in italics being the four on the basis of which an information was filed charging him to be a fourth offender. Brought into court on that limited charge, he acknowledged his identity as the convict in each of the previous cases and he was given a life sentence pursuant to the Act. He was without counsel and it is said that he was neither advised of his right to obtain counsel nor was counsel offered to him.3
It rather overstrains our credulity to believe that one who had been a defendant eight times and for whom counsel had twice waged defenses, albeit unsuccessful ones, did not know of his right to engage counsel. No request to do so appears. The only question of fact before the court on the fourth offender charge was whether he was the same person who was convicted in the four cases. This he then admitted and does not now deny. The only other question was sentence, and it does not appear that any information helpful to petitioner was unknown to the court.
*731It is said that the sentencing judge prejudiced the defendant by a mistake in construing the Pennsylvania Habitual Criminal Act in that he regarded as mandatory a sentence which is discretionary. It is neither clear that the sentencing court so construed the statute, nor if he did that we are empowered to pronounce it an error of Pennsylvania law. It is clear that the trial court, in view of defendant’s long criminal record, considered he had a duty to impose the life sentence and referred to it as one “required by the Act.” But there is nothing to indicate that he felt constrained to impose the penalty except as the facts before him warranted it. And it in any event is for the Pennsylvania courts to say under its law what duty or discretion the court may have had. Nothing in the record impeaches the fairness and temperateness with which the trial judge approached his task. His action has been affirmed by the highest court of the Commonwealth. We are not at liberty to conjecture that the trial court acted under an interpretation of the state law different from that which we might adopt' and then set up our own interpretation as a basis for declaring that due process has been denied. We cannot treat a mere error of state law, if one occurred, as a denial of due process; otherwise, every erroneous decision by a state court on state law would come here as a federal constitutional question.
We have just considered at length the obligation of the States to provide counsel to defendants who plead guilty to non-capital offenses. Bute v. Illinois, 333 U. S. 640. Notwithstanding the resourceful argument of assigned counsel in this Court, we think that precedent settles the issue here, that no exceptional circumstances are present and that, under the circumstances disclosed by the record before us, the State’s failure to provide counsel for this petitioner on his plea to the fourth offender charge did not render his conviction and sentence invalid.
*732Nor do we think the fact that one of the convictions that entered into the calculations by which petitioner became a fourth offender occurred before the Act was passed, makes the Act in validly retroactive or subjects the petitioner to double jeopardy. The sentence as a fourth offender or habitual criminal is not to be viewed as either a new jeopardy or additional penalty for the earlier crimes. It is a stiffened penalty for the latest crime, which is considered to be an aggravated offense because a repetitive one. Cf. Moore v. Missouri, 159 U. S. 673; McDonald v. Massachusetts, 180 U. S. 311; Graham v. West Virginia, 224 U. S. 616; Carlesi v. New York, 233 U. S. 51; Pennsylvania ex rel. Sullivan v. Ashe, 302 U. S. 51.
The judgment is
Affirmed.
§ 1108 of the Penal Code of 1939, 18 Pa. Stat. Ann. § 5108.
Respondent contested the case below and in this Court on the merits. We assume that the Supreme Court of Pennsylvania passed *730on petitioner’s allegations of deprivation of federal constitutional rights and that those issues are therefore open here. Herndon v. Lowry, 301 U. S. 242, 247.
The Supreme Court of Pennsylvania has frequently held that the state constitutional provision according defendants the right to be heard by counsel does not require appointment of counsel in non-capital cases. See, for example, Commonwealth ex rel. McGlinn v. Smith, 344 Pa. 41, 24 A. 2d 1; Commonwealth ex rel. Withers v. Ashe, 350 Pa. 493, 39 A. 2d 610. See also Betts v. Brady, 316 U. S. 455, 465. The Pennsylvania statutes require only that destitute defendants accused of murder shall be assigned counsel. Act of March 22, 1907, 19 Pa. Stat. Ann. § 784.