MR. JUSTICE WHITE delivered the opinion of the Court.

Appellees Clarence Ewell and Ronald Dennis were indicted on December 14, 1962, for selling narcotics without the order form required by 26 U.S.C. § 4705 (a) (1964 ed.). The indictments, each alleging a single sale, did not name the purchasers. After pleas of guilty on December 18 and December 19 they were sentenced to the minimum terms of imprisonment permitted by the statute, Dennis for five years and Ewell, as a second offender, for ten years. On July 17, 1963, the Court of Appeals for the Seventh Circuit, in an unrelated case, held that a § 4705(a) indictment that does not allege the name of the purchaser is defective and may be set aside under 28 U.S.C. § 2255 (1964 ed.). Lauer v. United States, 320 F.2d 187. Ewell's motion of November 6, 1963, to vacate his conviction, and Dennis' similar motion of January 28, 1964, were granted by the District Court on January 13 and April 13, 1964, respectively. Appellees were immediately rearrested on new complaints and reindicted, Ewell on March 26 and Dennis on June 15, 1964. These indictments, charging the same sales alleged in the original indictments but this time naming the purchasers, contained three counts: Count I charged violations of 26 U.S.C. § 4705 (a); Count II charged sales not in or from the original stamped packages in violation of 26 U.S.C. § 4704 (a) (1964 ed.); Count III charged dealing in illegally imported narcotics in violation of 21 U.S.C. § 174 (1964 ed.).

On July 13 and July 30, 1964, respectively, the United States District Court for the Southern District of Indiana granted the motions of Ewell and Dennis to dismiss the indictments against them on the ground that they had been denied their Sixth Amendment rights to a speedy trial, while rejecting their other contention that they were also being placed in double jeopardy. In its petition for rehearing on the dismissal of the indictment against Ewell, the Government advised the court that upon a plea or finding of guilty, all counts except that under 26 U.S.C. § 4704 (a) would be dismissed against him, leaving a conviction upon which the minimum sentence would be only five years for a second offender, in contrast to the minimum 10-year sentence which Ewell had previously received under § 4705(a). The court denied the request for rehearing and the Government then appealed directly to this Court from the dismissal of the indictments against Ewell and Dennis. 18 U.S.C. § 3731 (1964 ed.). The Government has limited its appeal to that portion of the order of the District Court in each case that dismissed the second count of each indictment, charging a violation of 26 U.S.C. § 4704 (a). We noted probable jurisdiction. 381 U.S. 909. We reverse.

We cannot agree that the passage of 19 months between the original arrests and the hearings on the later indictments itself demonstrates a violation of the Sixth Amendment's guarantee of a speedy trial. This guarantee is an important safeguard to prevent undue and oppressive incarceration prior to trial, to minimize anxiety and concern accompanying public accusation and to limit the possibilities that long delay will impair the ability of an accused to defend himself. However, in large measure because of the many procedural safeguards provided an accused, the ordinary procedures for criminal prosecution are designed to move at a deliberate pace. A requirement of unreasonable speed would have a deleterious effect both upon the rights of the accused and upon the ability of society to protect itself. Therefore, this Court has consistently been of the view that "The right of a speedy trial is necessarily relative. It is consistent with delays and depends upon circumstances. It secures rights to a defendant. It does not preclude the rights of public justice." Beavers v. Haubert, 198 U.S. 77, 87. "Whether delay in completing a prosecution . . . amounts to an unconstitutional deprivation of rights depends upon the circumstances. . . . The delay must not be purposeful or oppressive," Pollard v. United States, 352 U.S. 354, 361. "[T]he essential ingredient is orderly expedition and not mere speed." Smith v. United States, 360 U.S. 1, 10.

In this case, appellees were promptly indicted and convicted after their arrests in 1962 and were immediately rearrested and reindicted in due course after their § 2255 motions were granted in 1964. Moreover, it was the decision in Lauer v. United States, supra, and the subsequent vacation of appellees' prior convictions that precipitated the later indictments. In these circumstances, the substantial interval between the original and subsequent indictments does not in itself violate the speedy trial provision of the Constitution.

It has long been the rule that when a defendant obtains a reversal of a prior, unsatisfied conviction, he may be retried in the normal course of events. United States v. Ball, 163 U.S. 662, 671-672; United States v. Tateo, 377 U.S. 463, 465, 473-474. The rule of these cases, which dealt with the Double Jeopardy Clause, has been thought wise because it protects the societal interest in trying people accused of crime, rather than granting them immunization because of legal error at a previous trial, and because it enhances the probability that appellate courts will be vigilant to strike down previous convictions that are tainted with reversible error. United States v. Tateo, supra, at 466. These policies, so carefully preserved in this Court's interpretation of the Double Jeopardy Clause, would be seriously undercut by the interpretation given the Speedy Trial Clause by the court below. Indeed, such an interpretation would place a premium upon collateral rather than upon direct attack because of the greater possibility that immunization might attach.

Appellees themselves concede that Ball and Tateo are ample authority for retrial on charges under § 4705, despite their Sixth Amendment contentions. But they urge us to prohibit prosecution in their cases because the Government is proceeding under § 4704 rather than § 4705 and because the passage of time has allegedly impaired their ability to defend themselves on this new and different charge, thereby rendering the delay prejudicial and oppressive.

We note, first, however, that the new indictments charging violations of § 4704 were brought well within the applicable statute of limitations, which is usually considered the primary guarantee against bringing overly stale criminal charges. Surely appellees could claim no automatic violation of their rights to a speedy trial if there had been no charges or convictions in 1962 but only the § 4704 indictment in 1964. In comparison with that situation, the indictments and convictions of 1962 might well have enhanced appellees' ability to defend themselves, for they were at the very least put on early notice that the Government intended to prosecute them for the specific sales with which they were then and are now charged.

Second, the appellees' claim of possible prejudice in defending themselves is insubstantial, speculative and premature. They mention no specific evidence which has actually disappeared or has been lost, no witnesses who are known to have disappeared. Although the present charges allege sales not in or from the original stamped packages, under § 4704, rather than sales without the purchaser's written order form, under § 4705, the charges are based on the same sales as were involved in the previous indictments. In this respect, it should be recalled that the problem of delay is the Government's too, for it still carries the burden of proving the charges beyond a reasonable doubt.

Third, the new indictments occurred only after the vacation of the previous convictions; and the Government now seeks to sustain the § 4704 charges, which carry lesser minimum sentences than the charges under § 4705(a), not to oppress, but to extend to the trial judge, if these appellees are again convicted, the clear opportunity to take due account of the time both Ewell and Dennis have already spent in prison. We find no oppressive or culpable governmental conduct inhering in these facts.

The District Court apparently considered retrial and reconviction to be oppressive because appellees had already spent substantial time in prison and because in its view the law would not permit time already served to be credited against the sentences which might be imposed upon reconviction. This, too, is a premature concern. The appellees have not yet been convicted on the second indictments; and if they were to be reconvicted on § 4705 or § 4704 counts it should not be assumed that the controlling statute would prevent a credit for time already served. However that may be, as matters now stand, the remaining charges the Government seeks to sustain are under § 4704, which carries a minimum sentence in the case of Ewell of five years, as compared with a minimum of 10 years under § 4705, and two years instead of five years in the case of Dennis. In these circumstances, there is every reason to expect the sentencing judge to take the invalid incarcerations into account in fashioning new sentences if appellees are again convicted.

Appellees also invoke the Double Jeopardy Clause to sustain the dismissal of the indictments, a ground which we think the trial court correctly rejected. The Fifth Amendment provides that no person shall "be subject for the same offence to be twice put in jeopardy of life or limb." That clause, designed to prohibit double jeopardy as well as double punishment, is not properly invoked to bar a second prosecution unless the "same offence" is involved in both the first and the second trials. The identity of offenses is, therefore, a recurring issue in double jeopardy cases, but one which we need not face in this case. Here the Government is not attempting to prosecute a defendant for an allegedly different offense in the face of an acquittal or an unreversed conviction for another offense arising out of the same transaction. See Abbate v. United States, 359 U.S. 187, 196, separate opinion of MR. JUSTICE BRENNAN. Nor is there any question here of the Government's joining in one indictment more than one count allegedly charging the same crime. Compare Blockburger v. United States, 284 U.S. 299. Here, the Government seeks only to sustain one charge under § 4704. If the present indictments charge the same offense as the § 4705 offense for which appellees were previously convicted, they may clearly be retried on either § 4705 or § 4704 after their convictions have been vacated on their own motions. In these circumstances, where the appellees are subject to a second trial under Ball and Tateo, the fact that § 4704, rather than § 4705, is charged does not in any manner expand the number of trials that may be brought against them. If the two offenses are not, however, the same, then the Double Jeopardy Clause by its own terms does not prevent the current prosecution under § 4704. Reversed and remanded.