Treating the petition for rehearing en banc as a petition for panel rehearing, the petition for panel rehearing is GRANTED. The prior opinion, Moore v. Quarterman, 454 F.3d 484 (5th Cir.2006), is WITHDRAWN, and the following opinion is substituted:
Before SMITH, GARZA and DENNIS, Circuit Judges. JERRY E. SMITH, Circuit Judge:Eric Moore was convicted of capital murder and sentenced to death in 1991. In the wake of Atkins v. Virginia, 536 U.S. 304, 122 S.Ct. 2242, 153 L.Ed.2d 335 (2002), he filed a successive petition for habeas corpus relief in state court, arguing that he is mentally retarded and thus ineligible for the death penalty. The petition was dismissed as an abuse of the writ by the Texas Court of Criminal Appeals (“TCCA”).
This court granted Moore authorization to file a second federal habeas petition to raise an Atkins claim. The federal district court ultimately found him to be mentally retarded and accordingly granted the requested relief. But because Moore failed to exhaust the remedies available to him on his Atkins claim in state court, and because Texas’s abuse-of-the-writ-doetrine would preclude him from filing another petition based on facts he inexcusably failed to develop,1 we vacate and remand with instruction to dismiss the petition with prejudice.2
I.
A.
In December 1990 Moore and three other men broke into the home of Richard and Elizabeth Ayers, an elderly couple. The men robbed and shot the couple, killing Elizabeth Ayers and paralyzing Richard Ayers.
*216Moore was convicted of capital murder and sentenced to death in June 1991. He appealed his conviction and sentence, but the TCCA affirmed. Moore v. State, 882 S.W.2d 844 (Tex.Crim.App.1994), cert. denied, 513 U.S. 1114, 115 S.Ct. 909, 130 L.Ed.2d 791 (1995). Moore then filed his first petition for habeas relief in state court, which was denied. Ex parte Moore, No. 38,670-01 (Tex.Crim.App. Nov. 25, 1998) (unpublished). His first federal ha-beas petition likewise was denied. Moore v. Cockrell, No. 99-CV-18 (E.D.Tex. Nov. 26, 2001). A few months after Atkins had been decided, we affirmed the denial of the initial petition. Moore v. Cockrell, 54 Fed.Appx. 591 (5th Cir.2002) (table), cert. denied, 538 U.S. 965, 123 S.Ct. 1760, 155 L.Ed.2d 519 (2003).3
B.
In Atkins, 536 U.S. at 321, 122 S.Ct. 2242, the Court established for the first time that the execution of mentally retarded defendants violates the Eighth Amendment. After Atkins was decided, Moore filed a successive habeas petition in state court under Tex.Code Crim. Proc. art. 11.071 § 5(a), arguing that he is ineligible for the death penalty because he is mentally retarded and that this ground for relief was not available to him when he filed his first state habeas petition.4
Moore asserted mental retardation as indicated by his score of 74 on an IQ test taken when he was in grade school, his placement in special education throughout his schooling, and his history of head injuries, at least one of which occurred when he was nine or ten years old. To substantiate these claims, he cited to the trial record but provided no other evidence. He requested an “opportunity to be evaluated” and an evidentiary hearing, but the TCCA dismissed the successive petition as an abuse of the writ, asserting that Moore’s petition “fail[ed] to contain sufficient specific facts which would satisfy the requirements” of article 11.071 § 5(a). Ex Parte Moore, No. 38,670-02 (Tex.Crim.App. Feb. 5, 2003).
C.
Moore then sought permission from this court to file a second federal habeas petition. We allowed him to do so on the basis of 28 U.S.C. § 2244(b)(2)(A), finding that he had made a prima facie showing of entitlement to relief under Atkins sufficient to warrant further exploration of his claim. In re Moore, 67 Fed.Appx. 252 (5th Cir.2003) (table). We noted, however, that “the facts surrounding Moore’s alleged retardation have not been developed, and the parties have presented scant factual or legal grounds for us to assess the procedural default issue” that was raised by the state as a defense. Id.
We directed the district court to perform its own review of the record to determine whether Moore had met § 2244’s requirements for filing a successive habeas petition. If the district court was satisfied *217that those requirements had been met, it was instructed to consider the merits of Moore’s claim and the state’s defenses. Id.
D.
In his successive federal petition, unlike in his successive state petition, Moore lays out the three criteria used by the American Association on Mental Retardation (“AAMR”) to diagnose mental retardation and alleges reasons why he satisfies each.5 As in his state petition, he asserts that he scored a 74 on an IQ test when he was seven years old. He argues that this score indicates both subaverage intellectual functioning and an onset of retardation before age eighteen.6 He also contends that his poor performance in school and other events in his personal history that are a part of the trial record indicate a deficiency in the adaptive skill areas of functional academics, social skills, self-direction, and health and safety.7
On receiving Moore’s successive petition, the federal district court ordered a stay of execution. Hoping to develop the record in advance of a hearing on the merits of his claim, Moore then moved the court to authorize his counsel to obtain “expert investigatory services,” including a psychologist trained in the field of mental retardation and a mitigation investigator.
The district court denied the motion as premature and later denied the state’s motion to dismiss the petition, agreeing with us that Moore had met the § 2244(b)(2)(A) requirements for filing a successive habeas petition. Moore v. Johnson, No. 03-CV-224, 2003 WL 25321831 (E.D.Tex. May 15, 2003). Finding fault with the state court’s application of article 11.071 § 5(a), the court granted Moore habeas relief, ordering the state to release him from custody unless, within 180 days, it reopened his state habeas petition and conducted a fact-finding hearing to determine whether he is entitled to relief under Atkins. Moore v. Cockrell, No. 03-CV-224, 2003 WL 25321830 (E.D.Tex. July 28, 2003).
The state appealed, arguing that a district court can grant habeas relief only if it finds that a defendant is in custody in violation of the Constitution or laws or treaties of the United States. The state contended that the court’s determination that the state had misapplied its own procedural rule was not sufficient. Moore cross-appealed, arguing that he is entitled to an evidentiary hearing in federal court on his claim of mental retardation and that his claim is not procedurally defaulted.
We agreed with the state and vacated, instructing the court to determine on remand whether Moore is entitled to an evi-dentiary hearing and, regardless of whether it held such a hearing, whether Moore’s *218Atkins claim is procedurally defaulted. On a finding of no default, we directed the court to determine whether Moore is entitled to relief on the merits of his claim. Moore v. Dretke, 369 F.3d 844, 846 (5th Cir.2004).
E.
In June 2004, the district court issued an order stating it already had decided, in refusing to alter or amend the now-vacated writ, that there was no procedural default. Moore v. Dretke, No. 03-CV-224 (E.D. Tex. June 8, 2004).8 It granted an eviden-tiary hearing and, in doing so, rejected the state’s contention that Moore was not entitled to such a hearing under 28 U.S.C. § 2254(e)(2)(A) because he had failed factually to develop his Atkins claim in state court. The court held that § 2254(e)(2)(A) did not strip Moore of his entitlement to an evidentiary hearing, because it determined that Moore was prevented from developing his claim by the state court’s improper application of article 11.071 § 5(a). Id.
During the three-day hearing, Moore introduced the testimony of Dr. Antolin Lló-rente, a licensed psychologist who attested to Moore’s substandard intelligence and limitations in adaptive skills. He opined— based on his own interaction with Moore (including his administration of an additional IQ test) and his interviews of family members, friends, teachers, and employers^ — ’that Moore is mentally retarded. Moore proffered the direct testimony of various family members and friends, most of whom indicated that Moore had been “slow” and incapable of handling some of the basic requirements of daily living from an early age.
The state countered with the testimony of Dr. Gary Mears, a licensed and board-certified psychologist who had examined Moore. Mears asserted that Moore has good communication and interpersonal skills and was capable of recalling with clarity his early childhood experiences, his academic and work histories, and his criminal record. Mears examined Moore’s school and psychological testing records and concluded that although Moore is arguably of substandard intelligence, he is *219not deficient in any of the AAMR’s enumerated adaptive skill areas. Mears noted that Moore had in fact made a reasonable effort to succeed in life.
The state also challenged the validity of Moore’s IQ scores and emphasized that he had not in fact been in special education throughout his schooling. The state introduced the testimony of some of Moore’s teachers, who believed that his poor performance in an academic setting was not on account of substandard ability, but because of his disinterest and his refusal to apply himself.
The state also proffered the testimony of four correctional officers who had interacted with Moore on a daily basis. All of them indicated that Moore communicates well and successfully socializes with others.
Following the hearing, the district court again granted Moore habeas relief, holding that he is mentally retarded and thus ineligible for the death penalty pursuant to Atkins. Moore v. Dretke, No. 03-CV-224, 2005 WL 1606437 (E.D.Tex. July 1, 2005).9 The court found that the state court’s dismissal of Moore’s petition was not a ruling on the merits, but rather was an independent, though inadequate, application of article 11.071 § 5(a). The court therefore employed a de novo standard of review in assessing the merits of Moore’s claim, de-termming that no deference was owed to the state court’s ruling under the Anti-Terrorism and Effective Death Penalty Act of 1996 (“AEDPA”), 28 U.S.C. § 2254.
The state appeals, advancing three main arguments in the alternative: (1) Moore’s claim is procedurally defaulted under 28 U.S.C. § 2254(b)(1)(A) because he failed to exhaust his state court remedies before proceeding to federal court; the petition he filed with the TCCA amounted to a mere conclusional allegation of mental retardation that deprived the state court of the opportunity to rule on the substance of his claim; (2) the state court’s dismissal of Moore’s successive petition was merits-based and accordingly should be upheld given the deference it is owed under AED-PA; and (3) even if the district court was correct in employing a de novo standard, the district court’s factual findings with regard to Moore’s intellectual and adaptive functioning are' clearly erroneous, and its legal conclusion that Moore falls under the protection of Atkins is incorrect.10
II.
A.
In the district court, the state opposed Moore’s request for an evidentiary hearing on the basis of 28 U.S.C. § 2254(e)(2), *220arguing that Moore had failed factually to develop his Atkins claim in state court and thus should not be allowed such a hearing in federal court. On appeal the state contends that Moore’s presentation of new factual allegations, along with supporting evidence, in federal court that he did not include in his state petition implicates the exhaustion requirement of 28 U.S.C. § 2254(b)(1)(A). We have at least twice held that any problems presented by allegations and evidence introduced for the first time on federal review are “more accurately analyzed under the ‘exhaustion’ rubric .... ” Dowthitt v. Johnson, 230 F.3d 733, 745 (5th Cir.2000); see also Morris, 413 F.3d at 498.
B.
Under § 2254(b)(1)(A), “[a]n application for a writ of habeas corpus on behalf of a person in custody pursuant to the judgment of a State court shall not be granted unless it appears that the applicant has exhausted the remedies available in the courts of the State.” The exhaustion requirement “is not jurisdictional, but reflects a policy of federal-state comity designed to give the State an initial opportunity to pass upon and correct alleged violations of its prisoners’ federal rights.” Anderson v. Johnson, 338 F.3d 382, 386 (5th Cir.2003) (internal citations and quotations omitted). Whether a federal habeas petitioner has satisfied the exhaustion requirement is a question of law that we review de novo. Id.
C.
The exhaustion requirement is satisfied if petitioner has fairly “presented the substance of his claim to the state courts.” Vasquez v. Hillery, 474 U.S. 254, 258, 106 S.Ct. 617, 88 L.Ed.2d 598 (1986). The requirement is not satisfied if he “presents new legal theories or factual claims in his federal habeas petition. We have consistently held that a petitioner fails to exhaust state remedies when he presents material additional evidentiary support to the federal court that was not presented to the state court.” Anderson, 338 F.3d at 386. (internal citations and quotations omitted). Evidence is not material for exhaustion purposes if it “supplements, but does not fundamentally alter, the claim presented to the state courts.” Id. at 386-87. The failure to exhaust is a procedural bar to federal review that may be excused if the petitioner “can demonstrate cause for the defaults and actual prejudice.” Martinez v. Johnson, 255 F.3d 229, 239 (5th Cir.2001).
D.
The state argues that Moore’s successive state habeas petition was sparse to the point of amounting to a brief, conclu-sional allegation of mental retardation. The state emphasizes in particular that Moore made no allegations and offered no evidence before the TCCA with regard to his limitations in adaptive skill areas. The state contends that the presentation of such allegations and evidence for the first time in federal court fundamentally alters Moore’s Atkins claim, rendering it unex-hausted. We agree.
In Anderson, an “admittedly close case” on whether the petitioner had exhausted his state court remedies with respect to his ineffective assistance of counsel claim, this court asserted that the fact that “the portion of Anderson’s state post-conviction brief dedicated to ineffective assistance is remarkably detailed in both fact and law” provided the tipping point in favor of a finding of exhaustion. Anderson, 338 F.3d at 388. In Morris v. Dretke, 413 F.3d 484 (5th Cir.2005), an even more recent “admittedly close” case in which we addressed the question with which we are now *221faced — whether new evidence introduced in federal court rendered petitioner’s Atkins claim unexhausted — we similarly emphasized the importance of the detail with which the state petition was presented. Morris, 413 F.3d at 496.
The petitioner in Morris had not included an IQ score in his successive state habeas petition, because he lacked the funds to obtain the expert assistance required to administer such a test. After his state petition was dismissed, we allowed Morris to file a successive federal habeas petition, and the district court granted him leave to retain expert and investigative assistance. As a result, Morris was able to present a full-scale IQ score of 53 at the subsequent evidentiary hearing on the merits of his federal petition. Id. at 489.
The state contended that Morris’s Atkins claim was unexhausted because he had failed to present this IQ evidence to the state court. We disagreed, asserting that although, as in Anderson, Morris’s federal claim was “unquestionably in a comparatively stronger evidentiary posture than it was in state court,” several factors weighed in Morris’s favor. Id. at 496 (internal citations and quotations omitted). Most notably,
[Morris] ... properly outlined the AAMR’s definition for mental retardation, since adopted by the TCCA as one of Texas’s current standards for determining mental retardation, [Ex parte Briseno, 135 S.W.3d 1, 7-8 (Tex.Crim.App.2004)], and noted the necessity to meet all three essential prongs of the definition. See id. Morris also clearly acknowledged that IQ evidence was lacking in his particular case but still insisted “[t]here is good reason to believe that [Morris is retarded] ... because of the documented history of adaptive deficits,” including Morris’s “inability to read and write and his failure in functional academics,” “inability to obey the law and follow rules,” “inability to avoid victimization,” “inability to develop instrumentalities of daily living [and] occupational skills,” and “inability to maintain a safe environment,” all of which were attested to by the sworn affidavits and school records presented to the state courts.
Id. (emphasis added).
Furthermore, we acknowledged with approval that “Morris saw fit to present an expert affidavit [along with his state petition], which, albeit preliminarily, provided a psychologist’s acknowledgment of and support for Morris’s mental retardation claim.” Id. Finally, we noted that Morris had consistently asserted that “given the opportunity and resources, intellectual tests would confirm” his mental retardation. Id. Accordingly, we held that the state court had been given a fair opportunity to rule on the substance of Morris’s Atkins claim and that therefore his presentation of the IQ score for the first time on federal review supplemented, but did not fundamentally alter, that claim.
The successive habeas petition Moore filed with the TCCA pales in comparison to the one we considered in Morris. As we have discussed, Moore merely asserted in his petition that he had scored a 74 on an IQ test when he was a child, that he had been placed in special education throughout his schooling, and that he had suffered multiple head injuries, one of which occurred when he was no older than ten.
Moore cited to the trial record in support of these claims but offered neither school records nor supporting affidavits from family members, friends, teachers, or even the psychologist who had testified on his behalf at trial. He referenced neither the AAMR’s diagnostic criteria for mental retardation nor the similar definition of retardation contained in § 591.003 of the *222Texas Health and Safety Code.11 Most importantly, he failed to allege that he is deficient in two or more adaptive skill areas and indeed made no mention of adaptive limitations as such.
Moore’s contention that he was in special education throughout his schooling arguably could be construed as an allegation that he was only minimally functional in an academic setting. In support of that bare assertion, however, he did not “identify any specific special education classes or provide documentation of those classes,” Moreno, 450 F.3d at 164, nor did he offer any reason why he could not present such evidence. Moore’s petition did not touch, even arguably, on any other adaptive skill area, let alone explain why supporting evidence was lacking. Such a petition cannot be considered sufficiently “detailed in fact and law” to warrant a finding of exhaustion.
In Morris, 413 F.3d at 497, we noted that the AAMR’s three diagnostic criteria are interdependent and that evidence satisfying one prong is, “standing completely on its own,” not sufficient to avoid summary dismissal of an Atkins claim. Given that interdependence, it cannot be said that where a defendant’s state petition completely neglects one prong of the AAMR inquiry, the presentation of evidence in support of that prong on federal review merely supplements his Atkins claim.
It is true that Morris’s state petition was missing the allegation of a below-average IQ usually needed to support a finding of substandard intellectual functioning. The petition, however, “recognized the lack of [IQ] evidence in his record but noted various school records obtained by his counsel” were indicative of his subpar intelligence. Id. at 487. Moreover, the absence of IQ evidence in his state petition was appropriately explained by the fact that Morris at that time lacked the funds to obtain testing.
Moore, by contrast, neglected to specify his adaptive limitations and failed to provide a plausible excuse for why he could not present more than a scintilla of evidence on that prong. Indeed, there is no excuse for why he did not at minimum submit affidavits from his family members confirming his limitations in two or more areas of adaptive functioning. As was true in Dowthitt, 230 F.3d at 758, “[g]iven that the family members were willing to testify at a hearing, [Moore] could have easily obtained their affidavits [before he filed his petition in state court], A reasonable person in [his] place would have done at least as much .... Obtaining affidavits from family members is not cost prohibitive.”
E.
We recognize that the Atkins Court did not adopt a particular criterion for determining whether a defendant is mentally retarded; the Court instead left to the states “the task of developing appropriate ways to enforce the constitutional restriction .... ” Atkins, 536 U.S. at 317, 122 S.Ct. 2242. We also acknowledge that at the time Moore filed his petition, neither the Texas legislature nor the TCCA had developed a precise means of determining whether a criminal defendant qualifies for Atkins relief.
The Atkins Court, however, did reference the AAMR’s criteria and noted that most already-existing statutory definitions of mental retardation “conform to the *223clinical definitions .... ” Id. at 317 n. 22, 122 S.Ct. 2242. In addition, in Ex Parte Briseno, 135 S.W.3d 1, 7 (Tex.Crim.App.2004), the court stated that even before it officially adopted the AAMR’s criteria in the Atkins context, it had “previously employed” that definition in analyzing allegations of retardation relative to claims made under Penry v. Lynaugh, 492 U.S. 302, 109 S.Ct. 2934, 106 L.Ed.2d 256 (1989). Accordingly, it is fair to conclude that even for habeas petitions filed pre-Briseno, a petitioner has not adequately presented the substance of his Atkins claim to the TCCA unless he has, at the very least, (1) outlined either the AAMR criteria or the substantially equivalent § 591.003(13) definition of mental retardation and (2) either alleged why he satisfies each criterion or asserted reasons why he is currently incapable of presenting any evidence on a particular prong.
Moore’s state court petition is more akin to the type of conclusional allegation that we found insufficient to support exhaustion on an ineffective assistance of counsel claim in Kunkle v. Dretke, 352 F.3d 980 (5th Cir.2003), than it is to the robust claim of mental retardation presented to the state by the petitioner in Morris. Moore’s Atkins claim is therefore defaulted under 28 U.S.C. § 2254(b)(1)(A).
F.
We decline to excuse Moore’s failure to exhaust his state court claim. “The failure to exhaust is a procedural bar to federal review that may be excused if the petitioner can demonstrate cause for the defaults and actual prejudice.” Hillery, 474 U.S. at 260, 106 S.Ct. 617. Here, there was no cause; nothing “external to the petitioner” prevented him from at least referring to the test for mental retardation that had been discussed by the Supreme Court and had appeared in two other Texas authorities at the time of his petition, or from supplying school records or affidavits from family members attesting to his adaptive limitations.
Moore argues that, at the time he filed his petition, he did not know how extensive his fáctual pleading had to be to satisfy § 11.071 in the context of an Atkins claim. He did know, however, that Texas had to develop a standard to implement Atkins. He noted at oral argument that § 11.071 is analogous to the federal bar on successive habeas petitions, § 2254(b)(2)(A), which requires a petitioner to make a prima facie showing of entitlement to relief. It should have been obvious to him that
“[a] second or subsequent writ must contain ‘sufficient specific facts’ to support an applicant’s Atkins claim. A writ application which makes the naked assertion, T am mentally retarded,’ obviously does not suffice to leap over this second hurdle. If it did, every inmate on death row would be equally entitled to file a subsequent writ in the hope that something, somewhere, might turn up to support this bare assertion.”
Ex Parte Williams, 2003 WL 1787634, at *1 (Tex.Crim.App.2003) (Cochran, J., concurring) (unpublished).
Neither Williams nor Briseno had been decided when Moore filed his second state habeas petition, and we do not rigidly hold him to the pellucid standards announced in those cases; it is, nonetheless, reasonable to require him to cite a standard already mentioned by the Supreme Court in Atkins and on the books in two Texas authorities at the time of his petition and to supply (or argue credibly as to why he could not supply) evidence to support his claim.
As we have explained, Moore failed adequately to do this. To excuse his petition would be to excuse an inadequate and con-*224clusional filing that, for reasons not fairly attributable to factors outside the petitioner’s control, denied the state court its fair opportunity to develop a standard by which to implement Atkins and evaluate Moore’s petition.
Because our finding of unexcused failure to exhaust state remedies alone requires the dismissal of the petition, it is unnecessary to consider the state’s remaining arguments. Based on Moore’s default of his state court remedies, we VACATE the judgment granting the writ and REMAND with instruction to dismiss Moore’s Atkins claim with prejudice.
. See Tex.Code Crim. Proc. art. 11.071 § 5(a); Ex parte Graves, 70 S.W.3d 103, 114 (Tex.Crim.App.2002); Ex parte Kerr, 64 S.W.3d 414, 418 (Tex.Crim.App.2002).
. See Nobles v. Johnson, 127 F.3d 409, 420 (5th Cir.1997) (“Procedural default ... occurs when a prisoner fails to exhaust available state remedies and the court to which the petitioner would be required to present his claims in order to meet the exhaustion requirement would now find the claims procedurally barred.”).
. Neither Moore's initial state petition nor his initial federal petition requested relief on the basis of mental retardation.
. Article 11.071 § 5(a) states, in relevant part, that
[i]f a subsequent application for a writ of habeas corpus is filed after filing an initial application, a court may not consider the merits of or grant relief based on the subsequent application unless the application contains sufficient specific facts establishing that: (1) the current claims and issues have not been and could not have been presented previously in a timely initial application or in a previously considered application filed under this article or Article 11.07 because the factual or legal basis for the claim was unavailable on the date the applicant filed the previous application____
.The AAMR states that mental retardation “is characterized by [1] significantly subaverage intellectual functioning, existing concurrently with [2] related limitations in two or more of the following applicable adaptive skill areas: communication, self-care, home living, social skills, community use, self-direction, health and safety, functional academics, leisure, and work. [3] Mental retardation manifests before age 18.” Mental Retardation: Definition, Classification, and Systems of Supports 5 (9th ed.1992), quoted in Atkins, 536 U.S. at 309 n. 3, 122 S.Ct. 2242.
. Citing a psychiatric textbook, the Atkins Court, 536 U.S. at 309 n. 5, 122 S.Ct. 2242, noted that "an IQ between 70 and 75 or lower ... is typically considered the cutoff score for the intellectual function prong of the mental retardation definition.”
. In his successive state petition, Moore did not contend that he is limited in two or more adaptive skill areas. He makes this particular claim for the first time in his federal petition. In addition, he attaches portions of his school records to his federal petition, a step he did not take when he filed his state petition.
. "A federal court may not consider a state prisoner's constitutional claim if the state courts based their rejection of that claim on an adequate and independent state ground.” Emery v. Johnson, 139 F.3d 191, 194-95 (5th Cir.1998). If a state court rejects a habeas petition based on a purely procedural ground, rather than on a consideration of the merits of the constitutional claim, the dismissal is independent of that claim. As long as the application of the procedural rule is adequate (i.e., not arbitrary), it bars federal review of the constitutional claim. "It is not always easy, however, to determine whether a state court decision is based on state procedural grounds or, instead, on the court's interpretation of federal law.” Id. at 195.
The state court dismissed Moore's successive habeas petition for failure to meet the requirements of article 11.071 § 5(a). The federal district court initially determined that the state court's ruling did not result in a procedural default of Moore's Atkins claim for either one of two possible reasons: (1) The dismissal under article 11.071 § 5(a) is independent of the Atkins claim because all that the statute requires is an allegation of specific facts establishing that the factual or legal basis of the asserted claim was previously unavailable; the ruling is inadequate, however, because given that minimal procedural requirement, the dismissal of Moore's petition was arbitrary; or (2) the dismissal is not independent of the Atkins claim, because the TCCA performs a threshold merits inquiry under article 11.071 § 5(a).
When it later ruled on the merits of Moore’s Atkins claim, the court adopted only holding (1). See infra. The district court never ruled on whether, as the state contends on appeal, Moore's claim is procedurally defaulted under 28 U.S.C. § 2254(b)(1)(A) for failure to exhaust state court remedies.
. The court directed the state to release Moore from custody unless, within 180 days, it permanently stayed his execution or reformed his sentence to life imprisonment.
. Although the state represents in its briefs that it does not waive the argument that Moore’s Atkins claim is procedurally defaulted because the state court's dismissal was predicated on an independent and adequate state ground, the state offers no support for that argument other than to claim that “the issue is certainly debatable.” It instead spends much of its brief discussing the effect of the state court's ruling if it is in fact merits-based and thus not independent of Moore's constitutional claim. Because the state failed adequately to brief the issue of whether the state court’s dismissal of Moore’s successive petition provides an independent and adequate bar to federal habeas review, the argument is waived. See United States v. Martinez, 263 F.3d 436, 438 (5th Cir.2001). The state has not, however, waived its argument with regard to the particular reason for why there is no procedural default. Although the district court held that the state court dismissal was independent of the merits of Moore's Atkins claim, yet inadequate, the state contends that the dismissal arguably was not independent of the merits of the claim.
. " '[M]ental retardation’ means significantly subaverage intellectual functioning that is concurrent with deficits in adaptive behavior and originates during the developmental period.” Tex. Health & Safety Code § 591.003(13).