Justice Blackmun
delivered the opinion of the Court.
Article III of the Interstate Agreement on Detainers gives a prisoner incarcerated in one State the right to demand the speedy disposition of “any untried indictment, information or complaint” that is the basis of a detainer lodged against him by another State. These cases present the issue whether Art. Ill applies to detainers based on probation-violation charges.
I
The Interstate Agreement on Detainers (Agreement) is a compact among 48 States, the District of Columbia, Puerto Rico, the Virgin Islands, and the United States. The Agreement was drafted in 1956 by the Council of State Governments and was adopted in 1958 by the State of New Jersey, where it is now codified as N. J. Stat. Ann. §2A:159A-1 et seq. (West 1971). The Agreement is a congressionally sanctioned interstate compact within the Compact Clause, U. S. Const., Art. I, §10, cl. 3, and thus is a federal law subject to federal construction. Cuyler v. Adams, 449 U. S. 433, 438-442 (1981).
A detainer is a request filed by a criminal justice agency with the institution in which a prisoner is incarcerated, asking the institution either to hold the prisoner for the agency or to notify the agency when release of the prisoner is imminent. See id., at 436, n. 3 (citing and quoting H. R. Rep. No. 91-1018, p. 2 (1970), and S. Rep. No. 91-1356, p. 2 (1970)); United States v. Mauro, 436 U. S. 340, 359 (1978); Moody v. Daggett, 429 U. S. 78, 80-81, n. 2 (1976); Council of State Governments, Suggested State Legislation, Program for 1957, p. 74 (1956). Detainers generally are based on outstanding criminal charges, outstanding parole- or probation-violation charges, or additional sentences already imposed against the prisoner. See Dauber, Reforming the Detainer System: A Case Study, 7 Crim. L. Bull. 669, 676 (1971). See generally L. Abramson, Criminal Detainers (1979).
The Agreement is based on a legislative finding that “charges outstanding against a prisoner, detainers based on untried indictments, informations or complaints, and difficulties in securing speedy trial of persons already incarcerated in other jurisdictions, produce uncertainties which obstruct programs of prisoner treatment and rehabilitation.” Art. I. As has been explained:
“The inmate who has a detainer against him is filled with anxiety and apprehension and frequently does not respond to a training program. He often must be kept in close custody, which bars him from treatment such as trusty ships, moderations of custody and opportunity for transfer to farms and work camps. In many jurisdictions he is not eligible for parole; there is little hope for his release after an optimum period of training and treatment, when he is ready for return to society with an excellent possibility that he will not offend again. Instead, he often becomes embittered with continued institutionalization and the objective of the correctional system is defeated.” Council of State Governments, Suggested State Legislation, Program for 1957, p. 74 (1956).
See also Cuyler v. Adams, 449 U. S., at 449; United States v. Mauro, 436 U. S., at 353, 356, 359-360. Accordingly, the purpose of the Agreement is “to encourage the expeditious and orderly disposition of [outstanding] charges and determination of the proper status of any and all detainers based on untried indictments, informations or complaints.” Art. I.
To achieve this purpose, Art. Ill of the Agreement establishes a procedure by which a prisoner incarcerated in one party State (the sending State) may demand the speedy disposition of “any untried indictment, information or complaint on the basis of which a detainer has been lodged against the prisoner” by another party State (the receiving State). Specifically, Art. Ill requires the warden to inform the prisoner that a detainer has been lodged against him and that he may request final disposition of the indictment, information, or complaint upon which the detainer is based. If the prisoner makes such a request, the warden must forward it, together with a certificate providing certain information about the prisoner’s terms of confinement, to the appropriate prosecuting official and court of the receiving State. The authorities in the receiving State then must bring the prisoner to trial within 180 days, absent good cause shown, or the court must dismiss the indictment, information, or complaint with prejudice, and the detainer will cease to be of any force or effect.
II
On June 21, 1976, respondent Richard Nash, in the Superior Court of New Jersey, Law Division, Mercer County, pleaded guilty to charges of breaking and entering with intent to rape, and of assault with intent to rape. On October 29, the Superior Court sentenced respondent to 18 months in prison on each count, with the sentences to run consecutively. The court suspended two years of the sentences and imposed a 2-year term of probation to follow respondent’s imprisonment. On June 13, 1978, while on probation, respondent was arrested in Montgomery County, Pa., and charged with burglary, involuntary deviate sexual intercourse, and loitering. Respondent was tried and convicted on the Pennsylvania charges on March 14, 1979, and was sentenced on July 13 of that year.
While respondent was awaiting trial in Pennsylvania, the Mercer County Probation Department, on June 21, 1978, notified the Superior Court that respondent had violated his probation by committing offenses in Pennsylvania. At the Department’s request, the Superior Court issued a bench warrant for respondent’s arrest. The warrant was lodged as a detainer with the appropriate corrections officials in Pennsylvania.
Beginning on April 13, 1979, respondent sent a series of letters to New Jersey officials requesting final disposition of the probation-violation charge. The State of New Jersey failed to bring respondent “to trial” on the probation-violation charge within 180 days after Art. Ill was invoked.
On March 6, 1980, respondent filed a petition for a writ of habeas corpus in the United States District Court for the Middle District of Pennsylvania seeking dismissal of the probation-violation charge on the basis of the State’s noncompliance with Art. III. The case was transferred, pursuant to 28 U. S. C. § 1406(a), to the United States District Court for the District of New Jersey. App. to Pet. for Cert, in No. 84-776, p. 101. That court stayed respondent’s federal action pending exhaustion of state-court remedies. Id., at 81.
Respondent then petitioned for a writ of habeas corpus in New Jersey Superior Court. The Superior Court denied respondent’s motion to dismiss the probation-violation charge, ruled that respondent’s Pennsylvania convictions constituted a probation violation, and ordered respondent to serve the two consecutive 18-month sentences on his New Jersey convictions, with credit for 249 days respondent had served in 1976 and 1977. The Appellate Division affirmed the trial court’s judgment, id., at 44, and the New Jersey Supreme Court denied certification. Id., at 43.
Respondent then returned to the United States District Court for the District of New Jersey. On March 21, 1983, the District Court granted the petition for a writ of habeas corpus, vacated respondent’s probation revocation, and ordered his release from state custody. 558 F. Supp. 641 (1983). Petitioner Philip S. Carchman, the Mercer County prosecutor, took an appeal to the United States Court of Appeals for the Third Circuit. Petitioner State of New Jersey, Department of Corrections, at this point sought to intervene because the District Court’s decision invalidated its policy that parole- and probation-violation detainers do not fall within Art. Ill of the Agreement. Its motion to intervene was granted by the Court of Appeals. App. to Pet. for Cert, in No. 84-776, p. 18.
The Court of Appeals affirmed, holding that an outstanding probation-violation charge is an “untried indictment, information or complaint” within the meaning of Art. Ill of the Agreement. Nash v. Jeffes, 739 F. 2d 878 (1984). In reaching its decision, the Court of Appeals “decline[d] to adopt a technical interpretation of the relevant language of Article III,” id., at 883, and instead relied on “the broader purposes of the legislation.” Id., at 882. The court reasoned that a principal purpose of Art. Ill is to enable prisoners to obtain prompt disposition of the charges underlying detainers in order to protect them from the adverse consequences that detainers have on their treatment and rehabilitation, and that this purpose would be furthered by applying Art. Ill to detainers based on probation-violation charges. The Court of Appeals completed its “policy analysis,” id., at 883, n. 9, by concluding that the benefit to prisoners of applying Art. Ill to probation-violation detainers would outweigh the administrative burdens, including additional paperwork and the cost of transporting prisoners in order to provide them with probation-revocation hearings.
In view of the conflict, see n. 3, supra, we granted certio-rari. 469 U. S. 1157 (1985).
Ill
A
We begin by considering the language of the Agreement. Article III by its terms applies to detainers based on “any untried indictment, information or complaint.” The most natural interpretation of the words “indictment,” “information,” and “complaint” is that they refer to documents charging an individual with having committed a criminal offense. See Fed. Rules Crim. Proc. 3 (complaint) and 7 (indictment and information). This interpretation is reinforced by the adjective “untried,” which would seem to refer to matters that can be brought to full trial, and by Art. Ill's requirement that a prisoner who requests final disposition of the indictment, information, or complaint “shall be brought to trial within 180 days.” (Emphasis added.)
The language of Art. V also indicates that Art. Ill should be interpreted to apply solely to criminal charges. Article V(a) provides: “In response to a request made under Article III or Article IV hereof, the appropriate authority in a sending State shall offer to deliver temporary custody of such prisoner to the appropriate authority in the State where such indictment, information or complaint is pending against such person in order that speedy and efficient prosecution may be had.” (Emphasis added.) Article V(c) provides that “in the event that an action on the indictment, information or complaint on the basis of which the detainer has been lodged is not brought to trial within the period provided in Article III or Article IV hereof, the appropriate court of the jurisdiction where the indictment, information or complaint has been pending shall enter an order dismissing the same with prejudice, and any detainer based thereon shall cease to be of any force or effect.” (Emphasis added.) Finally, Art. V(d) provides: “The temporary custody referred to in this agreement shall be only for the purpose of permitting prosecution on the charge or charges contained in 1 or more untried indictments, informations or complaints which form the basis of the detainer or detainers or for prosecution on any other charge or charges arising out of the same transaction.” (Emphasis added.)
The language of the Agreement therefore makes clear that the phrase “untried indictment, information or complaint” in Art. Ill refers to criminal charges pending against a prisoner. A probation-violation charge, which does not accuse an individual with having committed a criminal offense in the sense of initiating a prosecution, thus does not come within the terms of Art. III. Although the probation-violation charge might be based on the commission of a criminal offense, it does not result in the probationer’s being “prosecuted” or “brought to trial” for that offense. Indeed, in the context of the Agreement, the probation-violation charge generally will be based on the criminal offense for which the probationer already was tried and convicted and is serving his sentence in the sending State.
Nor, of course, will the probationer be “prosecuted” or “brought to trial” on the criminal offense for which he initially was sentenced to probation, since he already will have been tried and convicted for that offense. Instead, the probation-violation charge results in a probation-revocation hearing, a proceeding to determine whether the conditions of probation should be modified or the probationer should be re-sentenced, at which the probationer is entitled to less than the full panoply of due process rights accorded a defendant at a criminal trial. See Gagnon v. Scarpelli, 411 U. S. 778 (1973). Cf. Morrissey v. Brewer, 408 U. S. 471 (1972) (parole-revocation hearing).
Respondent contends that Art. Ill applies to more than just criminal charges, relying principally on the language of Art. I, which provides: “The party States find that charges outstanding against a prisoner, detainers based on untried indictments, informations or complaints, and difficulties in securing speedy trial of persons already incarcerated in other jurisdictions, produce uncertainties which obstruct programs of prisoner treatment and rehabilitation.” (Emphasis added.) According to respondent, this language indicates that the drafters intended the Agreement to apply, literally, to all “charges outstanding against a prisoner,” including a probation-violation charge. However, when this language, which appears in the legislative declaration of purpose, is read in the context of the operative language of Arts. Ill and V discussed above, it is clear that the drafters meant the term “charges” to refer to criminal charges.
We therefore conclude from the language of the Agreement that a detainer based on a probation-violation charge is not a detainer based on “any untried indictment, information or complaint,” within the meaning of Art. III.
B
The legislative history of the Agreement does not persuade us to depart from what appears to be the plain language of the Agreement. Respondent relies principally on the following passage from comments made by the Council of State Governments, which drafted the Agreement:
“A detainer may be defined as a warrant filed against a person already in custody with the purpose of insuring that he will be available to the authority which has placed the detainer. Wardens of institutions holding men who have detainers on them invariably recognize these warrants and notify the authorities placing them of the impending release of the prisoner. Such detainers may be placed by various authorities under varying conditions, for example, when an escaped prisoner or a parolee commits a new crime and is imprisoned in another state; or where a man not previously imprisoned commits a series of crimes in different jurisdictions.” Suggested State Legislation, Program for 1957, p. 74 (emphasis added).
This passage is the introductory paragraph of the Council’s discussion of the suggested legislation. It was intended to provide a general definition of detainers and a brief description of how they might arise. The italicized passage suggests that some detainers arise from parole-violation charges, a fact not in dispute here. By its terms, however, Art. Ill does not apply to all detainers, but only to those based on “any untried indictment, information or complaint.” The above passage does not illuminate, or purport to illuminate, the scope of this phrase.
Indeed, if the above passage were interpreted to define the scope of Art. Ill, it would lead to the conclusion that Art. Ill applies to paro le- violation detainers. This conclusion is difficult to reconcile with the procedures established by the Agreement. In particular, the prisoner invokes Art. Ill by “caus[ing] to be delivered to the prosecuting officer and the appropriate court of the prosecuting officer’s jurisdiction written notice of the place of his imprisonment and his request for a final disposition to be made of the indictment, information or complaint.” (Emphasis added.) This notification mechanism is efficacious in the case of criminal-charge detainers, but not in the case of parole-violation detainers, because prosecutors and judges generally are not involved in parole-revocation proceedings. If the drafters of the Agreement had intended Art. Ill to apply to parole-violation de-tainers, they likely would have devised a more appropriate notification mechanism. Furthermore, Art. 111(d) provides that if the prisoner is returned to the original place of imprisonment without being tried on any indictment, information, or complaint, “the court shall enter an order dismissing the [indictment, information, or complaint] with prejudice.” Similarly, Art. V(c) provides that if the prisoner is not brought to trial within the period provided in Art. Ill, “the appropriate court of the jurisdiction where the indictment, information or complaint has been pending shall enter an order dismissing the same with prejudice.” (Emphasis added.) It is difficult to understand how these provisions would apply in the context of parole-violation charges, which generally are issued and adjudicated by a parole board or similar administrative agency, and are not “pending” in any court.
We therefore conclude that the reference to parolees in the comments of the Council of State Governments does not support the inference that in drafting the Agreement the Council intended the scope of Art. Ill to include detainers based on parole- or probation-violation charges.
In contrast to the legislative history created by the Council of State Governments, which does not directly address the precise issue in this case, the congressional legislative history indicates that Congress, which adopted the Agreement in 1970, see Pub. L. 91-538, 84 Stat. 1397, considered the Agreement to apply only to detainers based on untried criminal charges. The Court noted in United States v. Mauro, 436 U. S., at 359, and in Cuyler v. Adams, 449 U. S., at 436, n. 3, that the House and Senate Reports on the Agreement explain: “A detainer is a notification filed with the institution in which a prisoner is serving a sentence, advising that he is wanted to face pending criminal charges in another jurisdiction.” H. R. Rep. No. 91-1018, p. 2 (1970); S. Rep. No. 91-1356, p. 2 (1970) (emphasis added). The congressional Reports also contain references to the prisoner’s being “convicted on the new charges.” H. R. Rep. No. 91-1018, at 2; S. Rep. No. 91-1356, at 2. In addition, Senator Hruska stated in the congressional debates on the Agreement: “At the heart of this measure is the proposition that a person should be entitled to have criminal charges pending against him determined in expeditious fashion.” 116 Cong. Rec. 38840 (1970) (emphasis added).
C
As noted, the Court of Appeals said its decision was based not on “a technical interpretation of the relevant language of Art. Ill,” 739 F. 2d, at 883, nor on any statements in the legislative history addressing the specific issue in this case, but rather on “the broader purposes of the legislation,” id., at 882. We do not find that these purposes compel the conclusion that, contrary to the plain language of the Agreement, Art. Ill was intended to apply to probation-violation detainers.
Adoption of the Agreement was motivated in part by a practice of filing detainers based on untried criminal charges that had little basis. These detainers often would be withdrawn shortly before the prisoner was released. Even though unsubstantiated, the detainers would have a detrimental effect on the prisoner’s treatment. Article III enables a prisoner to require the State lodging the detainer either to drop the charge and resulting detainer or to bring the prisoner to trial. In this way, the prisoner can clear his record of detainers based on unsubstantiated charges.
A probation-violation detainer, however, generally, as in the present case, will be based on the prisoner’s commission of the crimes that resulted in his conviction and incarceration in the sending State. Because the convictions conclusively establish the probation violation, see Morrissey v. Brewer, 408 U. S., at 490 (parole revocation hearing), the probation-violation charge will not be unsubstantiated. Thus, the abuses that in part motivated adoption of the Agreement generally do not occur in the context of probation-violation detainers.
The Agreement generally seeks “to encourage the expeditious and orderly disposition of [outstanding] charges,” as well as the prompt “determination of the proper status of any and all detainers based on untried indictments, infor-mations or complaints,” in order to eliminate “uncertainties which obstruct programs of prisoner treatment and rehabilitation.” Art. I. The uncertainties associated with probation-violation detainers, however, are less severe than the uncertainties associated with criminal-charge detainers. See Dauber, Reforming the Detainer System: A Case Study, 7 Crim. L. Bull. 669, 680 (1971) (parole- and probation-violation detainers involve less uncertainty than criminal-charge de-tainers). As noted above, in general the factual issue of guilt of the probation violation is conclusively established by the convictions leading to incarceration in the sending State. Disposition of the probation-violation charge underlying a de-tainer therefore often will result in probation being revoked and in the probationer’s being resentenced to imprisonment in the receiving State. See Moody v. Daggett, 429 U. S., at 89 (parole violation); L. Abramson, Criminal Detainers 64-65, 81 (1979). The ultimate consequence is that the detainer based on the probation-violation charge merely will be replaced by a detainer based on the reimposed sentence, with similar adverse effects on the prisoner’s treatment and rehabilitation. See Dauber, swpra, at 678-679. Since the probation revocation is based on commission of a crime serious enough to warrant incarceration in the sending State, the probationer no doubt often, as in the present case, will be sentenced to serve the full term of his suspended sentence. Thus, the uncertainties in the underlying charge, in the likelihood of the prisoner’s receiving an additional sentence, and in the length of incarceration generally are less in the case of probation-violation detainers than in the case of criminal-charge detainers. Moreover, because the prisoner may not relitigate the factual issue of guilt of the probation-violation charge when it is established by a conviction in the sending State, see Morrissey v. Brewer, 408 U. S., at 490, the “most serious,” see Barker v. Wingo, 407 U. S. 514, 532 (1972), of the interests of the accused in obtaining a speedy disposition of outstanding criminal charges —the interest in “ ‘limiting] the possibilities that long delay will impair [his] ability ... to defend himself/” Smith v. Hooey, 393 U. S. 374, 378 (1969), quoting United States v. Ewell, 383 U. S. 116, 120 (1966)—is unlikely to be strongly implicated in the probation-violation detainer context.
Indeed, it often may be desirable to delay rather than to expedite disposition of the probation-violation charge. As the Court explained in Moody v. Daggett, 429 U. S. 78 (1976), in the context of parole violations:
“[I]n cases such as this, in which the parolee admits or has been convicted of an offense plainly constituting a parole violation, the only remaining inquiry is whether continued release is justified notwithstanding the violation. This is uniquely a ‘prediction as to the ability of the individual to live in society without committing antisocial acts.’ Morrissey, supra, at 480. In making this prophecy, a parolee’s institutional record can be perhaps one of the most significant factors. Forcing decision immediately after imprisonment would not only deprive the parole authority of this vital information, but since the other most salient factor would be the parolee’s recent convictions, ... a decision to revoke parole would often be foreordained. Given the predictive nature of the hearing, it is appropriate that such hearing be held at the time at which prediction is both most relevant and most accurate — at the expiration of the parolee’s intervening sentence.” Id., at 89.
Of course, the decision whether to request expeditious disposition lies with the prisoner, and there are circumstances under which the prisoner may have a legitimate interest in obtaining prompt disposition of a probation-violation charge underlying a detainer. For example, the prisoner may believe that he can present mitigating evidence that will lead to a decision not to revoke probation. Alternatively, he may hope for the imposition of a concurrent sentence. Finally, he simply may prefer the certainty of a known sentence to the relative uncertainty of a pending probation-violation charge.
Nevertheless, as discussed above, the purposes of the Agreement are significantly less advanced by application of Art. Ill to probation-violation detainers than by application of Art. Ill to criminal-charge detainers. Whether those purposes would be advanced sufficiently by application of Art. Ill to probation-violation detainers to outweigh the administrative costs, and, more generally, whether the procedures of Art. Ill are the most appropriate means of disposing of probation-violation detainers, are questions of legislative judgment that we must leave to the parties to the Agreement. Given the plain language of the Agreement and the relevant legislative history, we cannot conclude on the basis of the stated purposes of the Agreement alone that the parties to the Agreement intended Art. Ill to apply to probation-violation detainers. Accordingly, the judgment of the Court of Appeals is reversed.
It is so ordered.
Article 111(a) provides in pertinent part:
“Whenever a person has entered upon a term of imprisonment in a penal or correctional institution of a party State, and whenever during the continuance of the term of imprisonment there is pending in any other party State any untried indictment, information or complaint on the basis of which a detainer has been lodged against the prisoner, he shall be brought to trial within 180 days after he shall have caused to be delivered to the prosecuting officer and the appropriate court of the prosecuting officer’s jurisdiction written notice of the place of his imprisonment and his request for final disposition to be made of the indictment, information or complaint: provided that for good cause shown in open court, the prisoner or his counsel being present, the court having jurisdiction of the matter may grant any necessary or reasonable continuance.”
The District Court ruled that respondent’s letters requesting disposition of the detainer were sufficient to invoke Art. Ill, even though they did not strictly comply with Art. Ill’s request procedures. The Court of Appeals affirmed that ruling. We assume, without deciding, that this ruling on the issue whether respondent complied with the procedures of Art. Ill is correct.
This holding conflicts with rulings of the United States Court of Appeals for the Ninth Circuit and of four state courts of last resort. See United States v. Roach, 745 F. 2d 1252 (CA9 1984); Padilla v. State, 279 Ark. 100, 648 S. W. 2d 797 (1983); Suggs v. Hopper, 234 Ga. 242, 215 S. E. 2d 246 (1975); Clipper v. State, 295 Md. 303, 455 A. 2d 973 (1983); State v. Knowles, 275 S. C. 312, 270 S. E. 2d 133 (1980). It also conflicts with rulings of several intermediate state appellate courts. See, e. g., People v. Jackson, 626 P. 2d 723 (Colo. App. 1981); People ex rel. Capalongo v. Howard, 87 App. Div. 2d 242, 453 N. Y. S. 2d 45 (1982); Blackwell v. State, 546 S. W. 2d 828 (Tenn. Crim. App. 1976). See Nash v. Jeffes, 739 F. 2d 878, 881, n. 4 (CA3 1984) (citing cases involving parole- and probation-violation detainers).
Even if the term “charges” in Art. I were interpreted to refer to all charges, under normal rules of statutory construction the specific language of Art. Ill would control over the general language of Art. I.
For example, Art. Ill clearly does not apply to a detainer based on an additional sentence already imposed against the prisoner.
One commentator has noted:
“Since the legal basis for a detainer is rarely examined, a prisoner can suffer loss of privileges and parole because of a charge for which there is not sufficient proof to obtain an indictment. Undoubtedly, detainers are sometimes used by prosecutors to exact punishment without having to try a charge which they feel would not result in a conviction.” Note, Detain-ers and the Correctional Process, 1966 Wash. U. L. Q. 417, 423 (footnote omitted).
See also United States v. Mauro, 436 U. S. 340, 358, and n. 25 (1978) (noting that, because of the informality of the detainer system, detainers may be filed groundlessly or even in bad faith). The congressional Reports note that the Agreement provides the prisoner “with a procedure for bringing about a prompt test of the substantiality of detainers placed against him by other jurisdictions.” H. R. Rep. No. 91-1018, p. 2 (1970); S. Rep. No. 91-1356, p. 2 (1970).
According to the congressional Reports, “a majority of detainers filed by States are withdrawn near the conclusion of the Federal sentence.” H. R. Rep. No. 91-1018, at 3; S. Rep. No. 91-1356, at 3.
The United States Court of Appeals for the Eighth Circuit has described these effects as follows:
“[T]he inmate is (1) deprived of an opportunity to obtain a sentence to run concurrently with the sentence being served at the time the detainer is filed; (2) classified as a maximum or close custody risk; (3) ineligible for initial assignments to less than maximum security prisons (i. e., honor farms or forestry camp work); (4) ineligible for trustee [sic] status; (5) not allowed to live in preferred living quarters such as dormitories; (6) ineligible for study-release programs or work-release programs; (7) ineligible to be transferred to preferred medium or minimum custody institutions within the correctional system, which includes the removal of any possibility of transfer to an institution more appropriate for youthful offenders; (8) not entitled to preferred prison jobs which carry higher wages and entitle [him] to additional good time credits against [his] sentence; (9) inhibited by the denial of possibility of parole or any commutation of his sentence; (10) caused anxiety and thus hindered in the overall rehabilitation process since he cannot take maximum advantage of his institutional opportunities.” Cooper v. Lockhart, 489 F. 2d 308, 314, n. 10 (1973).
See Brief for University of Virginia School of Law Post-Conviction Assistance Project as Amicus Curiae 30-31 (“[I]n most eases the conviction for which the prisoner is serving a sentence will be conclusive proof of the violation”). Although a probation-violation detainer initially might be based on an arrest, the probationer cannot invoke Art. Ill until he “has entered upon a term of imprisonment in a penal or correctional institution of a party State” — that is, until he has been convicted of the offense in the sending State and commenced to serve his sentence there.
The Court of Appeals suggested that the Agreement serves “to vindicate a prisoner’s constitutional right to a speedy trial,” 739 F. 2d, at 883, but noted that this purpose is “not usually relevant when probation violations are involved.” Id., at 882. Some 13 years after the Agreement was drafted, this Court ruled that the Sixth Amendment right to a speedy trial entitles a prisoner in a federal penitentiary who is subject to pending state criminal charges to have the State, upon demand, make a diligent, good-faith effort to bring him to trial within a reasonable time. Smith v. Hooey, 393 U. S. 374 (1969). The congressional Reports discuss Smith v. Hooey and explain that enactment of the Agreement by Congress “would afford defendants in criminal cases the right to a speedy trial and diminish the possibility of convictions being vacated or reversed because of a denial of this right.” S. Rep. No. 91-1356, at 2. See also H. R. Rep. No. 91-1018, at 1-2; 116 Cong. Rec. 14000 (1970) (remarks of Rep. Poff); id., at 38840 (remarks of Sen. Hruska). Thus, Congress, at least, enacted the Agreement in part to vindicate a prisoner’s constitutional right to a speedy trial. This Court has never held, however, that a prisoner subject to a probation-violation .detainer has a constitutional right to a speedy probation-revocation hearing. Cf. Moody v. Daggett, 429 U. S. 78 (1976) (a prisoner in a federal penitentiary who is subject to a federal parole-violation detainer is not constitutionally entitled to a prompt parole-revocation hearing). Thus, as the Court of Appeals suggested, it is not clear that the purpose of vindicating a prisoner’s constitutional right to a speedy trial is applicable at all in the context of probation-violation detainers.
We note that some commentators have recommended, in light of the differences between probation-violation charges and criminal charges, that procedures different from those of Art. Ill be adopted for resolving probation-violation charges underlying detainers. See, e. g., L. Abramson, Criminal Detainers 81-83 (1979); Dauber, Reforming the Detainer System: A Case Study, 7 Crim. L. Bull. 669, 704-706 (1971).