concurring in part and dissenting in part:
Although I agree that Baqir’s claims of discrimination on the basis of race, color, religion, and national origin; hostile work environment; and retaliation fail as a matter of law, I cannot conclude that summary judgment is appropriate with respect to Baqir’s claim of age discrimination. Baqir has produced direct evidence that the sole reason for his termination was his age. Although the VA has produced evidence that Baqir was instead fired because of his performance, the question of what actually motivated the VA’s decision is for the fact-finder, not this Court, to resolve. I therefore respectfully dissent as to Part IV.B of the majority opinion.
The ADEA makes it unlawful “to discharge any individual ... because of such individual’s age.” 29 U.S.C. § 623(a)(1). Thus, the reason for the employer’s decision is the critical inquiry. Viewing the evidence in the light most favorable to Baqir, “age [was] the major and only factor” behind the VA’s decision to terminate him, as the majority recognizes.1 See J.A. *749197 (emphasis added). The majority also accepts that this statement is attributable to the actual decision-maker. We cannot grant summary judgment to the employer under these circumstances.
The majority believes that the VA may “avoid liability by proving that it would have terminated [Baqir] even in the absence of a discriminatory motive.” EEOC v. Warfield-Rohr Casket Co., 364 F.3d 160, 164 (4th Cir.2004). Although this is so for the traditional mixed-motive case, it is not a viable theory on summary judgment here, where not only is there direct evidence of discriminatory animus, but also that the discriminatory animus was the sole motive for his discharge.
The exceptional nature of Baqir’s evidence merits emphasis. Through Lewis Elliston’s statement, which has every indi-cia of reliability as it was made against his own interest, Baqir shows not just that age was one motive for his termination, but that it was the only motive behind his discharge. It is perhaps because such an admission is so unusual that the majority’s analysis goes astray. Typically, a plaintiff is only able to show that an employer exhibited age-based animus or that age was one of the motivating factors for its decision. In such circumstances, it is entirely appropriate to evaluate whether age made a difference to the outcome of the employer’s decision; liability is not appropriate if the legitimate factors that the employer actually considered alone supported its decision.
However, where, as here, a single illegitimate reason was the actual basis for the employer’s decision, the fact that an alternative legitimate basis might also have existed is without consequence. In the present case, Baqir’s evidence is that the VA did not consider his performance at all at the time it made its decision. Therefore, the VA cannot prevail at the summary judgment stage through evidence that legitimate considerations motivated its decision instead. Rather, the VA’s evidence creates an issue of fact regarding what its motives were.2
I note that all this is not to say that Baqir has proved his case. The VA may, of course, argue to the factfinder that Baqir’s performance was one of, if not the only reason it actually decided to terminate Ba-qir. As recounted by the majority, the VA has produced evidence that Elliston’s explanation for the VA’s decision is untrue. However, it is not our function on summary judgment to weigh the evidence and assess credibility. Anderson v. Liberty Lobby, Inc., 477 U.S. 242, 249, 106 S.Ct. 2505, 91 L.Ed.2d 202 (1986). Instead, we must only determine whether material facts remain in issue. Here, there is a genuine factual question as to what the VA’s actual motives were. Clearly, a rea*750sonable juror would be entitled to believe the very words attributable to the deci-sionmaker, stating that the sole reason Baqir was terminated was because of his age. Accordingly, summary judgment for the VA on Baqir’s age discrimination claim was inappropriate.
. Baqir's evidence of Lewis Elliston's statement, which Baqir’s wife recounted in her *749affidavit, need not be corroborated. See EEOC v. Warfield-Rohr Casket Co., 364 F.3d 160, 164 (4th Cir.2004). Nevertheless, I note that Elliston conceded that he related Baqir's termination to age in telling Baqir that inter-ventional cardiology was “a young man's sport.” See Pl.’s Br. in Opp'n to Def.'s Mot. for Summ. J. Ex. 3 at 25.
. Even under the traditional mixed-motive scenario, "[a]n employer may not ... prevail ... by offering a legitimate and sufficient reason for its decision if that reason did not motivate it at the time of the decision.” Price Waterhouse v. Hopkins, 490 U.S. 228, 252, 109 S.Ct. 1775, 104 L.Ed.2d 268 (1989) (plurality opinion). Thus, the question is not whether an employer "could have” terminated the employee regardless of his age, but whether the employer “would have” done so. See Warfield-Rohr, 364 F.3d at 164. Posthoc justifications have no effect under a statute concerned only with a defendant’s actual motives. Although the VA argues that it considered its legitimate motive contemporaneously with making its decision, the evidence is contradictory on this point.