¶1delivered the opinion of the Court
¶2We must determine whether a defendant may collaterally attack a prior judgment of conviction used to enhance a new offense, in the trial of that new offense, on the ground that the prior judgment was too lenient. We hold that he cannot.
¶3I. BACKGROUND
¶4A. Trial
¶5Appellant was serving time in prison for burglary (three years) and aggravated sexual assault (forty-five years). He was bench-warranted to Smith County to answer for a theft offense. While in the Smith County jail, he escaped. He was ultimately convicted on both the theft and escape charges. He was sentenced to two years in state jail for the theft and ten years in prison for the escape. The escape sentence was ordered to be run concurrently with the theft sentence. The written judgment for the escape conviction is silent as to whether the escape sentence was to run concurrently to or consecutively with appellant’s prior burglary and aggravated sexual assault sentences. This written judgment is also silent concerning whether or not there was a plea agreement.
¶6Appellant later committed more crimes and was ultimately charged with new felony offenses of escape, burglary of a habitation, and theft. The State alleged two prior judgments of conviction for enhancement purposes.
¶7*885The State presented three responses to appellant’s claim: (1) Article 42.08(b) did not require the escape judgment to be stacked because appellant was not actually “in” the prison system at the time of the escape, since he had been bench-warranted to the Smith County jail. (2) Even if the judgment had to be stacked, the absence of stacking did not make the judgment void and the deficiency could be corrected in a nunc pro tunc order. (3) Equitable notions of justice should prevent the defendant from gaining the benefit of concurrent sentencing and then turning around to complain about it later.
¶8The trial court denied appellant’s motion, the enhancement allegations were subsequently found to be true, and appellant was sentenced as an habitual offender on all three offenses, receiving sentences of thirty-three years, twenty-five years, and twenty-five years, respectively.
¶9B. Appeal
¶10In his sole point of error on appeal, appellant re-urged his contention that the Smith County escape judgment was void. In response, the State re-urged the first argument it had made at trial.
¶11The State filed a motion for rehearing, repeating its original argument and making the following additional arguments: (1) a prior conviction can be valid for enhancement purposes even if the sentence is void, (2) the trial court had no evidence before it that appellant met the criteria outlined in Article 42.08(b), (3) appellant bargained for the punishment obtained and cannot now complain of an action he earlier requested, and (4) a cumulation order is not part of the sentence. Appellant filed a response to the State’s motion. In responding to argument (3) above, appellant acknowledged that he “did enter into a plea bargain for his sentence in the Smith County escape case” but claimed that he did not “invite” the error as a result. The motion for rehearing was denied.
¶12En banc consideration was also requested but denied. In an opinion dissenting from the denial of en banc consideration, Justice Keyes argued that a cumulation *886order is not part of a sentence, so its absence could not render a sentence void.
¶13C. Discretionary Review
¶14In its petition for discretionary review, the State raises several issues, which can be summarized as follows: (1) whether appellant was estopped from complaining that his sentence was illegal, (2) whether a defendant’s constitutional rights would be violated by a nunc pro tunc order that would make the sentences run consecutively, (3) what is the legal effect of a failure to order a sentence to run consecutively as required by Article 42.08(b), and (4) what amount of evidence is required to invoke the mandatory provisions of Article 42.08(b).
¶15In arguing the estoppel question, the State claims that appellant entered into a plea agreement for his sentence on the Smith County escape charge. In his response brief, appellant contends that there is no evidence in the record to prove that his conviction was the result of an agreement.
¶16II. ANALYSIS
¶17We need not decide whether to treat this case as involving a plea agreement with respect to the concurrent sentencing issue. As we shall explain, if there was no plea agreement on the concurrent sentencing issue, then the judgment is not void, and thus not subject to collateral attack, because it was at some point in time subject to reformation.
¶18A. No Agreement Means Judgment Is Not Void
¶19Appellant’s challenge to the enhancement allegation in this case constitutes a collateral attack on the prior judgment of conviction.
¶20*888Initially, we point out that there is a difference between an entire judgment being “void” and a portion of a judgment being “void.” For example, a judgment may contain two or more sentencing elements (e.g. imprisonment and fine), one of which may be valid while the other is void.
¶21This Court has addressed at least three different curable judgment defects relating to punishment that arose from a contested trial, in which there was no plea agreement. In Williams v. State, we confronted on direct appeal a claim that a cumulation order was void.
¶22In Ex parte Johnson, an applicant claimed on habeas corpus that his conviction for aggravated robbery was void because it contained an unauthorized fine.
¶23In Barker v. State, the defendant did what appellant did here: he challenged a prior conviction used for enhancement purposes at the trial of a new offense.
¶24Clearly, where concurrent sentencing is not a part of a plea agreement, reforming the judgment to make the sentence consecutive can be accomplished without resort to resentencing. We have already held that a cumulation order can be deleted without disturbing the remainder of the judgment. Imposing a cumulation order where one is required is simply the flip side of the coin. This type of situation does not involve a range of valid possible punishment options that would require a new sentencing hearing to be held. If concurrent sentencing between two sentences (here the escape and the prior aggravated sexual assault) is invalid, then only one valid option remains (consecutive sentencing), making reformation possible, at the very least, on direct appeal.
¶25We need not decide whether the defect here is itself of the void or voidable variety,
¶26B. Agreement Means Appellant Is Es-topped from Challenging the Judgment
¶27This Court has not, in a majority opinion, addressed the application of the estoppel doctrine in circumstances such as these. But the issue was discussed in a plurality opinion on rehearing in Heath v. State
¶28An examination of the plurality opinion in Heath reveals that its holding on the estoppel issue was based upon a faulty premise. Immediately before reaching its conclusion, the plurality discussed Shannon v. State
¶29The Heath plurality then made an illogical leap: it assumed that the mistake made by the court of appeals in Shannon (which never applied the doctrine of estoppel) was somehow an assumption underlying the doctrine of estoppel.
¶30Acknowledging a “dearth of Texas case-*891law” on the subject,
¶31We have previously dealt in Prystash v. State with a type of estoppel involving unilateral requests that result in “invited error,” but estoppel is a flexible doctrine that manifests itself in various forms that are not limited to unilateral requests. The variant of estoppel at issue here is “estoppel by judgment.”
¶32Moreover, a close cousin of “estoppel by judgment” is “estoppel by contract,” where a party who accepts benefits under a contract is estopped from questioning the contract’s existence, validity, or effect.
¶33Indeed, courts in several other jurisdictions have held that a defendant cannot enter a plea agreement that imposes an illegal sentence, benefit from that sentence, and then attack the judgment later when it is suddenly in his interests to do so.
On the other hand, a defendant should not be allowed to reap the benefits of an illegal sentence, which is lighter than *892what the legal sentence would have been, and then turn around and attack the legality of the illegal, lighter sentence when it serves his interest to do so. Allowing such actions would [wreak] havoc upon the criminal justice system in this state. For example, all subsequent convictions and sentences of that defendant which are reliant upon the conviction concomitant with the illegal sentence would have to be set aside. This would result in a number of enhanced and habitual offender sentences being set aside for the very offender who had already enjoyed greater leniency than the law allows.55
¶34For the same reasons, that court refused to grant relief in a later case when the defendant challenged a prior unauthorized probation after it had been revoked and used to enhance a later offense.
¶35We find these cases persuasive. A defendant who has enjoyed the benefits of an agreed judgment prescribing a too-lenient punishment should not be permitted to collaterally attack that judgment on a later date on the basis of the illegal leniency.
¶36The judgment of the court of appeals is reversed, and the judgment of the trial court is affirmed.
¶37. See Tex. Pen.Code § 12.42(d).
¶38. Article 42.08(b) provides: "If a defendant is sentenced for an offense committed while the defendant was an inmate in the institutional division of the Texas Department of Criminal Justice and the defendant has not completed the sentence he was serving at the time of the offense, the judge shall order the sentence for the subsequent offense to commence immediately on completion of the sentence for the original offense.”
¶39.The court of appeals found that the State conceded in its brief that, under Fullbright v. State, 818 S.W.2d 808, 810 (Tex.Crim.App.1991), “if the trial court erred in failing to stack the Smith County escape sentence, then it cannot rely upon that conviction to enhance Rhodes’s convictions that are on appeal here.” Rhodes v. State, 175 S.W.3d 348, 352 (Tex.App.-Houston [1st Dist.] 2004). In its brief, the State said, “The State does not disagree with the Appellant on the nature of the law as to the use of convictions for purposes of enhancements as stated in Fullbright v. State.” We are uncertain that this concession is as expansive as the court of appeals has characterized it, but in any event, we are not bound by a party's concession on a matter of law. Long v. State, 931 S.W.2d 285, 289 (Tex.Crim.App.1996).
¶40. Because appellant was serving time for both the burglary and the aggravated sexual assault offenses at the time of the escape, Article 42.08 required the escape sentence to be stacked on the much longer sentence for the aggravated sexual assault conviction because it would be the last to terminate. See Basden v. State, 897 S.W.2d 319 (Tex.Crim.App.1995).
¶41. Rhodes, 175 S.W.3d at 350-55.
¶43. Id. at 356-59 (Keyes, J., dissenting from denial of en banc consideration).
¶44. The State's grounds for review are as follows:
First: This Court needs to decide whether a defendant can be estopped from complaining about an error capable of rendering a judgment or sentence void.
Second: This Court needs to decide whether a defendant can be estopped from complaining, after he enjoyed its benefits, that his sentence was illegal or void because it was below the statutory minimum.
Third: This Court needs to decide whether a defendant’s constitutional rights are violated when a trial court corrects a clerical error by changing a concurrent sentence to a statutorily mandatory consecutive sentence years after the defendant has begun to serve the sentence.
Fourth: This Court needs to determine the legal effect of the failure to order a sentence to run consecutively as ordered by 42.08(b) of the Texas Code of Criminal Procedure. Fifth: This Court needs to make a practical review of the question of what amount of evidence is required to invoke the mandatory provisions of Article 42.08(b).
¶45. Appellant’s main argument in his response brief is that the State forfeited review of its current claims by failing to raise them on original submission to the court of appeals. Arguably, the State's fifth ground for review is an extension of the arguments it did present on original submission to the court of appeals. Nevertheless, because the State prevailed at trial, we may in our discretion address subsidiary arguments that support the trial court’s ruling that were not presented to the court of appeals. Volosen v. State, 227 S.W.3d 77, 80 (Tex.Crim.App.2007).
¶46Judge Price contends that Volosen s holding is inconsistent with prior holdings in Rochelle v. State, 791 S.W.2d 121 (Tex.Crim.App.1990), and Sotelo v. State, 913 S.W.2d 507 (Tex.Crim.App.1995), and he contends that the holdings in those latter cases would bar our disposition of the current case. But Rochelleand Soteloare distinguishable because, in both cases, the petitioner’s ground for review did not challenge any holding of the court of appeals, while Volosenand the present case involve grounds that do challenge a holding of the court of appeals, but for reasons not addressed by the lower appellate court.
¶47In Rochelle, the State advanced a procedural default ground for review that did not challenge the court of appeals’s holding that the indictment was fatally defective. 791 S.W.2d at 122, 125. In Sotelo, the defendant’s claim that a remand for a new punishment hearing violated double jeopardy principles was not a challenge to the court of appeals’s holding that the trial court had erroneously quashed the State’s enhancement allegations. 913 S.W.2d at 508-09. By contrast, in Volosen, the State’s grounds for review directly challenged the court of appeals’s holding that the evidence was legally insufficient to support the defendant’s conviction because the defendant had established a defense as a matter of law — though the argument supporting the State’s challenge had not been considered by the court of appeals. 227 S.W.3d at 79-80. Similarly, in the present case, the arguments we consider today respond directly to the court of appeals's holding that the prior conviction *887was not available for enhancement purposes, although those arguments were not discussed in the court of appeals’s opinion.
¶48This is the same sort of position the parties are in when the case is before a court of appeals. The party who loses at the trial level must address both the trial court’s ruling and the rationale for that ruling, see Tex.R.App. P. 33.1(a)(l)(A)(party complaining about trial proceedings must have stated grounds for ruling), (2)(A)(party complaining about trial proceedings must have obtained a ruling), but the party who wins at the trial level can prevail on appeal on the basis of a rationale not addressed by the trial court, see State v. Herndon, 215 S.W.3d 901, 905 n. 4 (Tex.Crim.App.2007)("the general rule is that a trial court’s ruling will be upheld if it is correct on any applicable legal theory, even if the court articulated an invalid basis”). The point of Vola-sen is that the parties’ positions in this regard are fixed at trial and do not change during the subsequent course of appellate litigation. Thus, the party who loses at the trial level who then complains about a decision of the court of appeals must address both the holding and the reasoning of the court of appeals, but the party who wins at the trial level who complains about a decision of the court of appeals need only address the holding of the court of appeals.
¶49. An agreement to concurrent sentencing would be to the State’s disadvantage if estop-pel does not apply, because if there is no agreement, then the sentence is reformable. See discussion below.
¶50. Although the ten-year sentence for the Smith County escape was the maximum for a third-degree felony, the record suggests that the offense could have been enhanced to a second-degree felony with either the prior burglary or the prior sexual assault conviction. See Tex. Pen.Code § 12.42(a)(3)(West 1998).
¶51. Because of this holding, we need not address whether a defendant could be estopped to attack a judgment even when there was no plea agreement.
¶52. New v. State, 583 S.W.2d 781, 782 (Tex.Crim.App.1979).
¶54. See Ex parte Johnson, 697 S.W.2d 605 (Tex.Crim.App.1985)(imprisonment was within the range of punishment, but fine exceeded the range of punishment).
¶55. Id. at 607-08; Barker v. State, 169 Tex.Crim. 277, 278-79, 334 S.W.2d 182, 183-84 (1960).
¶56. Rhodes v. State, 560 S.W.2d 665, 667 (Tex.Crim.App.1978)(quoting Barker, 169 Tex.Crim. at 279, 334 S.W.2d at 184)("A judgment or sentence containing an irregularity which may be reformed on appeal or by nunc pro tunc entry is not void, and may not be collaterally attacked.”); Smothermon v. State, 383 S.W.2d 929, 931 (Tex.Crim.App.1964)(“could have been reformed in a proper proceeding”); Ex parte Brown, 145 Tex.Crim. 39, 42, 165 S.W.2d 718, 720 (1942)(‘‘upon the original appeal of this case, it could have been reformed”).
¶57. Rhodes, 560 S.W.2d at 667.
¶58. 675 S.W.2d 754, 760 (Tex.Crim.App.1984).
¶62. id. at 607-08.
¶66. Id.(citing Ex parte King, 156 Tex.Crim. 231, 240 S.W.2d 111 (1951)).
¶67. Id.(citing Lenore v. State, 137 Tex.Crim. 417, 129 S.W.2d 657 (1939)).
¶68. See Ex parte Townsend, 137 S.W.3d 79, 80-82 (Tex.Crim.App.2004)(challenge to stacking order as invalid due to defendant’s status not cognizable on habeas corpus when it could have been raised on direct appeal).
¶69. See Langs v. State, 183 S.W.3d 680, 686 (Tex.Crim.App.2006)(double jeopardy, multiple punishment violation can be forfeited when the violation is not clear on the face of the record and forfeiture would serve the interests underlying the rules of procedural default).
¶70. See State v. Ross, 953 S.W.2d 748, 750 (Tex.Crim.App.1997)(for purpose of State’s appeal, "sentence” includes whether the term of imprisonment is concurrent); but see Speth v. State, 6 S.W.3d 530, 535 (Tex.Crim.App.1999)(Womack, X, concur-ringXcriticizing use of statutory definition of "sentence” to determine what this Court means when it says a sentence is void).
¶71. We need not and do not decide whether the State now has any remedy that would enable it to cumulate the prior escape sentence, or whether the State’s own use of the prior judgment to enhance the current offense would estop the State from utilizing such a remedy.
¶72. 817 S.W.2d 335, 337-40 (Tex.Crim.App.l991)(plurality opinion on rehearing).
¶73. 65 S.W.3d 656, 658-60 (Tex.Crim.App.2001)(Keller, P.J., concurring).
¶74. See Heath and Williams, supra. The opinion on original submission in Heath has been overruled on the basis that probation is not a part of the sentence. Williams, 65 S.W.3d at 657-58 (Court’s op.).
¶76. 65 S.W.3d at 658-60 (Keller, P.J., concurring).
¶77. Id. at 658 (Court's op.)("probation” is not part of the sentence and the defendant failed to show harm).
¶78. Mizell v. State, 119 S.W.3d 804, 806 n. 8 (Tex.Crim.App.2003)(citing concurrence in Williams and citing Collins v. State, 509 N.E.2d 827 (Ind.1987)).
¶79. Heath, 817 S.W.2d at 339-40 (discussing Shannon v. State, 708 S.W.2d 850 (Tex.Crim.App.1986)).
¶81. Id.at 339-40 (citing Shannon, 708 S.W.2d at 851).
¶82. Id.at 340 (citing Shannon, 708 S.W.2d at 851).
¶85. See Heath, 817 S.W.2d at 340.
¶86. Williams, 65 S.W.3d at 659 (Keller, P.J., concurring).
¶87. 3 S.W.3d 522 (Tex.Crim.App.1999).
¶88. See Williams, 65 S.W.3d at 658-660.
¶89. 31 C.J.S. Estoppel & Waiver % 130.
¶91. Id., p. 566; see also Williams, 65 S.W.3d at 659-60 (Keller, PJ. concurring)(discussing cases).
¶92. 31 C.J.S. Estoppel & Waiver § 124, p. 554.
¶93. People v. Hester, 22 Cal.4th 290, 295, 92 Cal.Rptr.2d 641, 992 P.2d 569, 572 (2000)(‘ 'defendants who have received the benefit of their bargain should not be allowed to trifle with the courts by attempting to better the bargain through the appellate process"); Collins, 509 N.E.2d at 833 ("a defendant may not enter a plea agreement calling for an illegal sentence, benefit from that sentence, and then later complain that it was an illegal sentence”); Punta v. State, 806 So.2d 569, 570 (Fla.App. 3rd DCA 2002) (quoting Bashlor v. State, 586 So.2d 488 (Fla.App. 1st DCA 1991))("sentences which are imposed in violation of statutory requirements, which are to the benefit of the defendant and to which he agreed, may not be challenged sifter the defendant has accepted the benefits flowing from the plea, but has failed to carry out the conditions imposed on him”); Graves v. State, 822 So.2d 1089, 1091 (Miss.App.2002)(defendant "cannot stand mute when he is handed an illegal sentence which is more favorable than what the legal sentence would have been, reap the benefits of that illegal sentence, and later claim to have been prejudiced as a result thereof”); Pruitt v. State, 846 So.2d 271, 274 (Miss.App.2002)("A convicted felon may not quietly enjoy the benefits of an illegally lenient sentence, and later attack the sentence when suddenly it is in his interest to do so”).
¶94. Graves, 822 So.2d at 1092.
¶95. Pruitt, 846 So.2d at 274.
¶96. We express no opinion today on whether estoppel could apply to bar a challenge to a judgment imposing a punishment that is illegally harsh, nor do we express an opinion on whether estoppel would bar a direct attack on a judgment imposing an illegally lenient punishment. See Williams, 65 S.W.3d at 660 (Keller, P.J., concurring)(observing that it could be persuasively argued that a defendant who appeals his conviction has not yet accepted the benefits of the illegal judgment).