concurring, in which Judge MOORE joins.
Although I concur in Chief Judge Boggs’ opinion for the Court, I write separately to emphasize an important issue regarding the standard of review that governs our consideration of this habeas petition.
Because the district court concluded that the Michigan Court of Appeals had ruled on the merits of Brown’s ineffective assistance of counsel, claim, the district court applied AEDPA’s deferential standard of review under 28 U.S.C. § 2254(d). We now reject the district court’s conclusion that such deference is appropriate, and, for the reasons set forth in Chief Judge Boggs’ opinion for the Court, instead conclude that Brown’s claims are subject to de novo review despite the fact that the Michigan Court of Appeals purported to resolve that claim on the merits. While I concur in this conclusion, our holding that deference under AEDPA is inappropriate under these circumstances bears further consideration.
In reaching this conclusion, we have relied on a line of cases from this Court and our sister circuits holding that AEDPA’s deferential standard of review does not apply where substantial new evidence is presented in support of a petitioner’s Brady claim. Our decision here expressly recognizes that this same principle “applies generally” to a broader universe of claims. In that respect, our decision today represents a natural but important progression of this body of case law.
I.
In many cases, ambiguities in the record make it difficult to determine whether the state courts resolved a particular claim “on the merits” for purposes of 28 U.S.C. § 2254(d). See Harris v. Reed, 489 U.S. 255, 261, 109 S.Ct. 1038, 103 L.Ed.2d 308 (1989). Here, however, there is no serious question that Brown pressed his ineffective assistance of counsel claim before the state courts, asserting, just as he does in his federal habeas petition, that his trial counsel failed to investigate whether Parsons’ counseling records contained pertinent information necessary to his defense. Brown, however, was unable to present critical evidence in support of that claim. Despite all indications that Parsons’ counseling records contained information necessary to Brown’s defense, Brown’s trial counsel entirely failed to pursue the matter. Nevertheless, the Michigan Court of *436Appeals denied Brown’s request for a Gin-ther hearing.1 People v. Brown, No. 227953, 2003 WL 133055, at *6 (Mich.Ct. App. Jan.3, 2003). Instead, the Michigan Court of Appeals expressly “limited” its review of Brown’s claim “to mistakes apparent on the record.” Id. at *2. As a result, Brown, through no fault of his own, was left without access to whatever information Parsons and her counseling records may have been able to offer in support of his Strickland claim.
The Michigan Court of Appeals thus never considered significant evidence that would have supported Brown’s claim. Nevertheless, without knowing what information Parsons’ records may have yielded, the Michigan Court of Appeals held that “the decision whether to present the victim’s counselor in order to impeach the victim was a matter of trial strategy,” and concluded that Brown had “failed to overcome the presumption of sound trial strategy or show[ ] that there [was] a reasonable probability that counsel’s failure to call this witness deprived him of a substantial defense or otherwise affected the outcome.” Id. at *4. In so ruling, the Michigan Court of Appeals appears to have resolved Brown’s Strickland claim “on the merits.”
Under AEDPA, that fact typically requires deference to the state court adjudication. This Court, however, has recognized that an important exception to the deference owed state courts under AED-PA exists where substantial new evidence in support of a petitioner’s claim arises during federal habeas proceedings. See, e.g., Joseph v. Coyle, 469 F.3d 441, 469 (6th Cir.2006). In such cases, we have construed the development of new evidence as giving rise, in effect, to a new claim, and thus we have held that deference is not required under § 2254(d).
That is precisely the case here. Because the Michigan courts refused to permit Brown to pursue evidence critical to his Strickland claim, Brown was never able to press the specific claim he raises here: whether, in light of the information contained in Parsons’ records, Brown’s trial counsel performed deficiently. As a result, there is no relevant state court adjudication of the merits of Brown’s claim to which we could defer. Under such circumstances, as Chief Judge Boggs’ opinion explains, the deference due state court adjudications under AEDPA is inapposite and inappropriate.
What Chief Judge Boggs’ opinion leaves unstated, however, is that our holding today represents an important and natural progression of this Court’s prior jurisprudence in this area. Until today, this Court has abandoned AEDPA’s deferential standard of review based on new evidence only in the limited context of Brady claims. See, e.g., Joseph, 469 F.3d at 469 (“If [petitioner] were now bringing the same Brady claim, i.e., one premised on the same suppressed evidence, then it would be a ‘claim that was adjudicated on the merits in State court proceedings,’ and we would review the state court’s decision only for whether it ‘was contrary to, or involved an unreasonable application of, clearly established Federal law, as determined by the Supreme Court of the United States.’ ”). A number of other circuits also have reached the same conclusion in the context of Brady claims. E.g., Monroe v. Angelone, 323 F.3d 286, 297 (4th Cir.2003) (“AEDPA’s deference requirement does not apply when a claim made on federal habeas review is premised on Brady material that *437has surfaced for the first time during federal proceedings.”); Rojem v. Gibson, 245 F.3d 1130, 1140 (10th Cir.2001) (reviewing Brady claim de novo when exculpatory-material was presented for first time in federal habeas proceedings). In each of these cases, the federal courts declined to apply AEDPA’s deferential standard of review because the petitioner identified substantial new evidence that was never considered by the state courts.
Today we conclude that, although most of these decisions have arisen in the context of Brady claims, there is no basis for limiting the rule to such claims. Rather, as we hold today, this principle “applies generally ” whenever substantial evidence supporting a habeas claim comes to light during a petitioner’s federal habeas proceedings, or whenever the reviewing state court improperly limits the scope of its review when considering a defendant’s federal constitutional claim.
II.
Our broader application of Joseph follows directly from the language of the statute and comports with this Court’s relevant jurisprudence. By its very terms, AEDPA applies only to habeas claims that were “adjudicated on the merits in State court....” 28 U.S.C. § 2254(d). Thus, regardless of the nature of a petitioner’s claim, deference is required only where the state courts in fact adjudicated a claim “on the merits.” Where, however, the state court did not assess the merits of a claim properly raised in a habeas petition, the deference due under AEDPA does not apply. Wiggins v. Smith, 539 U.S. 510, 534, 123 S.Ct. 2527, 156 L.Ed.2d 471 (2003); Maples v. Stegall, 340 F.3d 433, 436 (6th Cir .2003).
The lesson of Joseph and other such cases is that there is no state court adjudication “on the merits” to which the federal courts could defer when evidence critical to a petitioner’s claim was never before the state courts. See 469 F.3d at 469. Regardless of whether the state courts have purported to resolve a particular claim on the merits, the federal courts are obliged to determine whether that claim in fact was addressed by the state courts. See, e.g., Cargle v. Mullin, 317 F.3d 1196, 1206-07 (10th Cir.2003) (“Neither of these decisions assessed the aggregate prejudice arising from the several constitutional errors we find here. Thus, our cumulative-error review is not restricted by § 2254(d)(l)’s limited focus.... ”); Killian v. Poole, 282 F.3d 1204, 1208 (9th Cir.2002) (“AEDPA deference does not apply to [a petitioner’s] perjury claim ... [when] [evidence of the [claim] was adduced only at the hearing before the [federal] magistrate judge.”).
Building on Joseph, the import of our holding here is that this principle applies generally, regardless of the nature of the claim presented. Because AEDPA does not apply where critical evidence in support of a petitioner’s claim was never considered by the state courts, the availability of significant new evidence demands that the federal courts take a fresh look at that claim. See Holland v. Jackson, 542 U.S. 649, 653, 124 S.Ct. 2736, 159 L.Ed.2d 683 (2004) (noting that “[w]here new evidence is admitted, some Courts of Appeals have conducted de novo review on the theory that there is no relevant state-court determination to which one could defer” and “[a]ssuming ... that this analysis is correct and that it applies where ... the evidence does not support a new claim but merely buttresses a previously rejected one”); Monroe, 323 F.3d at 299 n. 19 (noting that de novo review is not appropriate whenever only “a scintilla of new exculpatory material comes to light in federal proceedings”). Although AEDPA im*438poses a requirement of deference to state court adjudications, “[w]e can hardly defer to the state court on an issue that the state court did not address.” Fortini v. Murphy, 257 F.3d 39, 47 (1st Cir.2001). In such circumstances, federal habeas review of that claim “is not circumscribed by a state court conclusion.” Wiggins, 539 U.S. at 534, 123 S.Ct. 2527.
Simply put, deference under AEDPA is inappropriate, and not required by statute, where significant new evidence relevant to a petitioner’s claim becomes available during federal habeas proceedings or the state courts improperly failed to consider significant evidence relevant to that claim. In this case, because the newly-available evidence is central to Brown’s Strickland claim, we must make an independent assessment of whether this evidence supports habeas relief.
. Under Michigan law, a defendant asserting an ineffective assistance of counsel claim may request a Ginther hearing to develop an evi-dentiary record to support his claim. See People v. Ginther, 390 Mich. 436, 212 N.W.2d 922, 924 (1973).