delivered the opinion of the Court.
In this case our jurisdiction is questioned by the State of Florida because the judgment of the Supreme Court of that State, which we are asked to review and which was rendered without opinion, may have rested upon an adequate state ground. For the reasons hereafter stated, we find that to be true with the result that we have no jurisdiction to entertain this petition or to consider the merits of the federal questions suggested by petitioner. While we thus deem petitioner’s allegations of fact as to the merits of this case to be irrelevant here, we imply nothing as to their truth or falsity, and we refrain from any discussion that depends upon or assumes their truth.
In 1945, petitioner Durley was convicted by a jury in the Criminal Court of Record for Polk County, Florida, on two informations. In each he was charged, in three counts, with stealing cattle.1 In the first count of the first information it was charged that, on July 7, 1945, petitioner, with two others, stole two steers from a Mrs. Bronson; in the second count, two cows; and in the third count, one heifer. The three counts of the other information charged that the same men on July 29, 1945, stole from a Mr. Zipperer a cow and two heifers, each of the animals allegedly stolen being the subject of a separate count. Petitioner was sentenced to serve five years’ imprisonment on each count, the terms to be served consecutively, thus making a total of 30 years.
Petitioner did not appeal from his conviction but, in 1949, labeling his petition a writ of error coram nobis, he, *279pro se, unsuccessfully sought relief. In the same year, also pro se, he filed a petition for a writ of habeas corpus in the Supreme Court of Florida claiming that he was confined in violation of the Fifth Amendment to the Federal Constitution because he had been tried on informa-tions rather than on indictments, that the verdict rested on perjured testimony,2 and that he had been denied a hearing on his petition for a writ of error coram nobis. This petition for habeas corpus was denied by the Supreme Court of Florida, without opinion, on the ground that petitioner failed to show probable cause that he was held without lawful authority.
In 1952, with the aid of court-appointed counsel, petitioner filed a petition for a writ of habeas corpus in a Florida Circuit Court. There he claimed that the infor-mations upon which he had been convicted charged the commission of only two, rather than six, offenses and that he already had served sufficient time to satisfy a ten-year sentence which would have been the maximum sentence permissible for two such offenses. Petitioner also charged that his imprisonment was in violation of his rights under the Constitution of the United States. A writ was issued, a return was filed, and the court heard argument of counsel for each side. The writ was quashed. Petitioner appealed to the Supreme Court of Florida, where his appeal was dismissed without opinion.
In 1955, petitioner, again pro se, instituted the present proceeding by filing in the Supreme Court of Florida another petition for a writ of habeas corpus. In it he claimed, inter alia, that his detention was an “abuse of the Due Process Clause of the 14th Amendment to the Constitution of the United States . . and that his con*280secutive sentences not only violated the Federal and State Constitutions, but were contrary to a recent decision of the Supreme Court of Florida, citing Hearn v. Florida, 55 So. 2d 559. That petition was argued in the Supreme Court of Florida by counsel for the State, although neither petitioner nor his counsel was present. The petition was denied, without opinion, again on the ground that petitioner failed to show probable cause that he was held without lawful authority.
A rehearing was denied but petitioner’s application for a writ of certiorari was granted by this Court, 350 U. S. 872, and counsel was appointed by this Court to represent him here, 350 U. S. 900. The case was fully briefed and argued on the jurisdictional issue as well as on the merits.
The State of Florida has objected consistently to our entertaining jurisdiction of this proceeding. Its reason is that the Florida Supreme Court’s denial of the 1955 petition for a writ of habeas corpus may have rested upon one or both of two adequate state grounds. Those grounds are (1) that, under Florida law, the issues presented in 1955 already had been rendered res judicata by the 1952 litigation, and (2) that, in any event, petitioner was precluded from raising the federal issues presented in 1955 because he had failed to raise them in comparable prior proceedings where he had a fair and adequate opportunity to do so.
The State’s claim as to res judicata rests primarily upon Fla. Stat. Ann., 1943, § 79.10, which provides that, while a judgment denying a petition for a writ of habeas corpus remains in force, no person “shall be at liberty to obtain another habeas corpus for the same cause, or by any other proceeding to bring the same matter again in question except by a writ of error or by action of false imprisonment . . . .”
*281Florida’s other state ground is based upon its Supreme Court decisions, and particularly upon Washington v. Mayo, 77 So. 2d 620, 621. It is there stated that “The rule is clear that a convicted prisoner should not be heard to raise in a subsequent proceeding, whatever its nature, issues that were previously raised and determined, or that the prisoner had a fair and adequate opportunity to raise and have determined in earlier proceedings.”
In the face of these expressions of the law of Florida, petitioner, in order to establish our jurisdiction, must demonstrate that neither of these state grounds can account for the decision below. “Where the highest court of the state delivers no opinion and it appears that the judgment might have rested upon a nonfederal ground, this Court will not take jurisdiction to review the judgment.” Stembridge v. Georgia, 343 U. S. 541, 547.
“It is a well established principle of this Court that before we will review a decision of a state court it must affirmatively appear from the record that the federal question was presented to the highest court of the State having jurisdiction and that its decision of the federal question was necessary to its determination of the cause. Honeyman v. Hanan, 300 U. S. 14, 18; Lynch v. New York, 293 U. S. 52. And where the decision of the state court might have been either on a state ground or on a federal ground and the state ground is sufficient to sustain the judgment, the Court will not undertake to review it. Klinger v. Missouri, 13 Wall. 257, 263; Wood Mowing & Reaping Machine Co. v. Skinner, 139 U. S. 293, 297; Allen v. Arguimbau, 198 U. S. 149, 154-155; Lynch v. New York, supra. . . . But it is likewise well settled that if the independent [state] ground was not a substantial or sufficient one, ‘it will be presumed that the State court based its judgment on the law *282raising the Federal question, and this court will then take jurisdiction.’ Klinger v. Missouri, supra, p. 263; Johnson v. Risk, 137 U. S. 300, 307; Lawrence v. State Tax Commission, 286 U. S. 276, 282-283.” Williams v. Kaiser, 323 U. S. 471, 477-478.
While the federal questions relied upon by petitioner in 1955 are not set forth by him as clearly as they might be, we do not rely upon that inadequacy.3
Petitioner argues that § 79.10 does not embody the traditionally broad doctrine of res judicata. He suggests that the statute bars only the relitigation of questions and matters that have been specifically presented and decided. By thus construing § 79.10, he argues that none of the precise federal issues raised in the 1955 petition were sufficiently raised and considered under his previous petitions. However, the Supreme Court of Florida has treated § 79.10 as applying the general rule of res judicata. See Florida ex rel. Cacciatore v. Drumbright, 116 Fla. 496, 156 So. 721; Florida ex rel. Williams v. Prescott, 110 Fla. 261, 148 So. 533; D’Alessandro v. Tippins, 102 Fla. 10, 137 So. 231. It even has applied that doctrine without reference to § 79.10. See Florida ex rel. Davis v. Hardie, 108 Fla. 133, 146 So. 97. On the other hand, it has, at times, treated habeas corpus petitions as barred by § 79.10 only where the issues have been raised and decided in a prior proceeding. See Moat v. Mayo, 82 So. 2d 591; Lee v. Tucker, 42 So. 2d 49; Pope v. Mayo, 39 So. 2d 286; and *283compare Florida ex rel. Williams v. Prescott, supra; Florida ex rel. Davis v. Hardie, supra.
In its more recent cases, the Supreme Court of Florida has held that, on an original application for habeas corpus, the petitioner may not raise issues that have been raised in prior proceedings whatever those may have been. Also, that unless he can show good reason for his failure to do so, he is precluded from raising issues which he could have raised in any such prior proceedings. Washington v. Mayo, 77 So. 2d 620; Irvin v. Chapman, 75 So. 2d 591; Florida ex rel. Johnson v. Mayo, 69 So. 2d 307. 4 In arguing before us that the issues now raised were or were not raised in prior proceedings, the parties have relied somewhat upon cases from this Court to support their arguments. Those decisions are not squarely in point because *284the issue before us is not one of federal law. The issue before us on res judicata is whether, under Florida law, petitioner was or was not free to raise in the Supreme Court of Florida in 1955 the questions he attempted to raise there. We conclude that the Supreme Court of Florida might have rested its denial of the 1955 petition on the grounds that the several federal issues presented to it in 1955 had been previously raised within the meaning of § 79.10 and, therefore, could not be raised again under the state practice, or at least could have been raised in the prior proceedings and, accordingly, under the above decisions they likewise were not available as a matter of state law.5
Petitioner further suggests that, under Florida law, the doctrine of res judicata will “not be so rigidly applied as to defeat the ends of justice.” Universal Construction Co. v. Fort Lauderdale, 68 So. 2d 366, 369. Relying on that case, petitioner argues that the application of res judicata is within the discretion of the court, but that case does not provide the necessary authority for that conclusion. In that case, the Supreme Court of Florida, exercising traditional common-law and equitable powers, created an exception to the common-law doctrine of res judicata because of an “unusual situation” confronting it. Id., at 370. The question before us is whether, under the facts of this case, the Supreme Court of Florida must necessarily read a similar exception into an Act of the legislature. We find no authoritative basis for doing so.
Finally, it is suggested that the order of the Florida court denying the 1955 petition shows affirmatively that the court decided the petition on the merits of the federal questions raised. We do not so read it. At most it is *285inconclusive and leaves room for a decision on the state grounds indicated in § 79.10 or by Washington v. Mayo, supra. The language of the order is that petitioner “failed to show . . . probable cause to believe that he is detained in custody without lawful authority . . . .” That is stated in the standard form used in habeas corpus proceedings. We find nothing on its face showing that the court must have decided the case on federal grounds rather than on the readily available and substantial state grounds.
Inasmuch as the Supreme Court of Florida's denial of the 1955 petition might have rested on either of the state grounds now suggested by the State, petitioner has failed to establish our jurisdiction to decide the federal issues that he urges upon us. He has not shown that they have been passed upon by the highest court of his State.
For lack of jurisdiction, the case, therefore, must be
Dismissed.
“811.11 Horse or cattle stealing
“Whoever commits larceny by stealing any horse, mule, mare, filly, colt, cow, bull, ox, steer, heifer or calf, the property of another, shall be punished by imprisonment in the state prison not less than two years nor more than five years.” Fla. Stat. Ann., 1944.
There was no allegation in this or the subsequent petition that the prosecution knowingly used perjured testimony as in Mooney v. Holohan, 294 U. S. 103.
The 1955 petition for habeas corpus and the petition for certiorari to this Court were drafted by petitioner. In similar circumstances, this Court has held that “where the substance of the claim is clear, we should not insist upon more refined allegations than [such a person] could be expected to supply.” Tomkins v. Missouri, 323 U. S. 485, 487; Rice v. Olson, 324 U. S. 786, 791-792; Holiday v. Johnston, 313 U. S. 342, 350. Florida follows the same practice. Ex parte Amos, 93 Fla. 5, 12, 112 So. 289, 292; Chase v. Florida ex rel. Burch, 93 Fla. 963, 968, 113 So. 103, 106.
While it is true that in the Johnson and Irvin cases the issues sought to be raised in the habeas corpus proceeding could have been raised on direct appeal, the court held that the writ was not available because the petitioners had failed to raise those issues in “prior proceedings.” These included a writ of error coram nobis in Johnson and a previous trial on the merits in Irvin.
It is suggested that the Washington case does not preclude this Court from taking jurisdiction because in that case the court, while stating the rule that would preclude jurisdiction, did consider on its merits a nonfederal contention which had not been previously raised. But assuming that the contention so considered had involved a substantial federal question, this Court would have lacked jurisdiction to review the judgment for the reason that it might have rested upon the adequate state ground. For our purposes, therefore, the discussion of the merits in that case may be treated as dicta.
Furthermore, the contention considered on its merits in the Washington case “apparently was not raised upon the earlier proceeding . . . .” 77 So. 2d, at 622. In the instant case, the perjury issue was presented in the 1949 petition, although not in terms of a federal constitutional issue. The Washington case, therefore, is certainly no authority for a conclusion in the instant case that any issues growing out of the previously raised issue, that the conviction rested upon perjured testimony, could be raised in the proceeding which is before us.
Our discussion of the Florida law is solely for the purpose of determining whether the test for our jurisdiction is met. We do not intimate that, under that law, petitioner is foreclosed from seeking any further remedial process that may be open to him.