BLACKWELL, Justice.

Terry Gene Tolbert was tried by a Richmond County jury and convicted of murder and the unlawful possession of a firearm during the commission of a felony, both in connection with the fatal shooting of Shelley Griffin. Tolbert appeals, contending only that he was denied the effective assistance of counsel. Upon our review of the record and briefs, we see no error, and we affirm.1

1. Viewed in the light most favorable to the verdict, the evidence shows that Leroy Sims and Dewey Sims are brothers, and Tolbert is their nephew. On January 26, 1996, following the execution of a search warrant at the residence at which Griffin lived, Griffin confronted Leroy, threatened him, and said that both Leroy and Dewey were "snitches." Griffin retrieved a pistol and then returned to complain more about the search. At that point, Dewey and Tolbert arrived at the scene, both carrying guns. Dewey and Tolbert joined Leroy, and all three quickly approached Griffin. Griffin gave his gun to a friend and urged Leroy, Dewey, and Tolbert not to use guns, but instead to fight "like a man." According to an eyewitness, Tolbert told Griffin: "Don't move, don't move, or I'm going to bust you." At some later point, Tolbert said: "[O]kay, you know. We ain't going to do nothing like that." Leroy then told Dewey to "do it" — or something along those lines — and Dewey then pointed a gun at Griffin and shot him in the head, killing him. Dewey, Leroy, and Tolbert then fled together. Although Tolbert does not dispute the legal sufficiency of the evidence, we have reviewed the entire record, and we conclude that the evidence adduced at trial was legally sufficient to authorize a rational trier of fact to find beyond a reasonable doubt that Tolbert is guilty of the crimes of which he was convicted.2 Jackson v. Virginia, 443 U.S. 307, 319(III)(B), 99 S.Ct. 2781, 61 L.Ed.2d 560 (1979).

2. Tolbert contends that he was denied the effective assistance of counsel at his trial because his lawyer also represented Leroy, and the concurrent representation of these two co-defendants, Tolbert says, created a conflict of interest for the lawyer. This conflict of interest, Tolbert argues, affected the way in which the lawyer represented him at trial in two distinct ways. First, he says, the lawyer did not seek out a favorable plea bargain for Tolbert, presumably because such a plea bargain might have involved Tolbert testifying against Leroy. Second, Tolbert contends, his lawyer did not argue at trial that he was less culpable than Leroy, an argument that would have been supported by the evidence, he claims, but one that posed a risk of highlighting the greater culpability of Leroy. We will address these arguments in turn, but we first recall the applicable principles of law.

(a) This Court has recognized the potential for serious conflicts of interest when one lawyer represents co-defendants in a criminal proceeding. See In re Formal Advisory Opinion 10-1, 293 Ga. 397, 400(2), 744 S.E.2d 798 (2013). Even so, the concurrent representation of co-defendants is not a "per se [violation] of constitutional guarantees of effective assistance of counsel." Burger v. Kemp, 483 U.S. 776, 783(III), 107 S.Ct. 3114, 97 L.Ed.2d 638 (1987) (citation and punctuation omitted). See also Ellis v. State, 272 Ga. 763, 765(2), 534 S.E.2d 414 (2000), overruled on other grounds, Alexander v. State, 297 Ga. 59, 62, 64, 772 S.E.2d 655 (2015). To prevail on a claim that a conflict of interest worked a denial of the effective assistance of counsel, a defendant like Tolbert — one who failed to object to the conflict at trial3 — must show that "an actual conflict of interest adversely affected his lawyer's performance." Cuyler v. Sullivan, 446 U.S. 335, 348(IV)(B), 100 S.Ct. 1708, 64 L.Ed.2d 333 (1980) (footnote omitted). See also State v. Mamedov, 288 Ga. 858, 860, 708 S.E.2d 279 (2011). As we consider whether Tolbert has made such a showing, we do not, however, inquire "into actual conflict as something separate and apart from adverse effect." Mickens v. Taylor, 535 U.S. 162, 172, n. 5(II), 122 S.Ct. 1237, 152 L.Ed.2d 291 (2002). Rather, as the United States Supreme Court has explained, an "actual conflict of interest" means "a conflict that affected counsel's performance — as opposed to a mere theoretical division of loyalties." Id. at 171(II), 122 S.Ct. 1237 (emphasis in original). See also Sullivan, 446 U.S. at 350(IV)(C), 100 S.Ct. 1708 ("the possibility of conflict is insufficient to impugn a criminal conviction"); Lamb v. State, 267 Ga. 41, 42(1), 472 S.E.2d 683 (1996) ("[T]he conflict must be palpable and have a substantial basis in fact. A theoretical or speculative conflict will not impugn a conviction which is supported by competent evidence.") (citation omitted). Put another way, the test of a claim that a conflict of interest worked a denial of the effective assistance of counsel is "whether the representation deprived either defendant of the undivided loyalty of counsel, i.e., did counsel slight one defendant to favor the other?" Lamb, 267 Ga. at 42(1), 472 S.E.2d 683 (citation omitted).4

Tolbert first asserted a conflict of interest of the part of his trial lawyer in a motion for new trial, and on that motion, he had the burden of proving that his trial lawyer had an actual conflict of interest, that is, one that significantly and adversely affected the adequacy of the representation. See State v. Abernathy, 289 Ga. 603, 604(1), 715 S.E.2d 48 (2011); Lamb, 267 Ga. at 42(1), 472 S.E.2d 683. In an attempt to carry his burden, Tolbert relied principally on the record of the trial, his own testimony at the hearing on his motion for new trial, and the testimony of Leroy at that same hearing. Notably, Tolbert did not elicit any testimony in support of his motion from his trial lawyer, inasmuch as the trial lawyer had passed away by the time that the motion for new trial was heard. The unavailability of his trial lawyer, however, did not relieve Tolbert of his burden. See Hicks v. State, 295 Ga. 268, 276, n. 7(3)(b), 759 S.E.2d 509 (2014); Schofield v. Meders, 280 Ga. 865, 867, n. 2(1), 632 S.E.2d 369 (2006).

In its order denying the motion for new trial, the trial court applied the proper standard and concluded that Tolbert had failed to carry his burden of proving that the trial lawyer was "laboring under a conflict of interest that adversely affected his representation." In support of this conclusion, the trial court made the following written findings of fact:

As we review the decision of the trial court, we owe no deference to its application of the law to the facts of this case. See Moon v. State, 288 Ga. 508, 514(8), 705 S.E.2d 649 (2011). See also Abernathy, 289 Ga. at 604(1), 715 S.E.2d 48; Davis v. Turpin, 273 Ga. 244, 248(3)(c), 539 S.E.2d 129 (2000). We owe substantial deference, however, to the way in which the trial court assessed the credibility of witnesses and found the relevant facts. See Moon, 288 Ga. at 514(8), 705 S.E.2d 649. To that end, we must accept the factual findings of the trial court unless they are clearly erroneous, see id., and we must view the evidentiary record in the light most favorable to the findings and judgment of the trial court. Cf. Brown v. State, 293 Ga. 787, 803(3)(b)(2), 750 S.E.2d 148 (2013) (in the context of appellate review of grant of motion to suppress, noting that deference to the fact-finding prerogative of the trial court requires an appellate court to view the evidence in the light most favorable to the findings and decision of the trial court). With these principles in mind, we turn now to the ways in which Tolbert claims that his representation was actually and substantially affected by a conflict of interest.

(b) To begin, we consider the contention that the trial lawyer for Tolbert and Leroy had a serious conflict of interest. As we have acknowledged before, in most every case in which one lawyer represents co-defendants in a criminal proceeding, there is, at the least, a potential conflict of interest, see In re Formal Advisory Opinion 10-1, 293 Ga. at 400(2), 744 S.E.2d 798, and we accept that there was some potential for a conflict of interest in this case. See Burns v. State, 274 Ga.App. 687, 689-690(1), 618 S.E.2d 600 (2005) ("the potential for an actual conflict of interest is greater in those cases in which multiple co-defendants are represented by a single attorney than when co-defendants are represented by different attorneys"), aff'd 281 Ga. 338, 638 S.E.2d 299 (2006). Tolbert asserts, however, that the danger posed here by the potential conflict of interest was compounded by the method by which the lawyer was paid and the ways in which he communicated with his concurrent clients.

At the hearing on the motion for new trial, Leroy testified that he paid the fee for the trial lawyer to represent both Tolbert and Leroy. We have recognized that, "in some circumstances[,] counsel's fee arrangement may create a conflict of interest with the client and the conflict can affect the adequacy of counsel's representation." Blackshear v. State, 274 Ga. 842, 844(2), 560 S.E.2d 688 (2002) (citations omitted). See also Wood v. Georgia, 450 U.S. 261, 268-269(III), 101 S.Ct. 1097, 67 L.Ed.2d 220 (1981) (noting "the inherent dangers that arise when a criminal defendant is represented by a lawyer hired and paid by a third party, particularly when the third party is the operator of the alleged criminal enterprise"). If Leroy alone paid the lawyer, that certainly could have provided an incentive for the lawyer to prioritize the interests of Leroy over those of Tolbert. See Mamedov, 288 Ga. at 861, 708 S.E.2d 279.

To make matters worse, Tolbert says, the lawyer met with Leroy alone, but he never met with Tolbert outside the presence of Leroy. At the hearing on the motion for new trial, Leroy testified that he met with the lawyer on several occasions on which Tolbert was not present.5 Tolbert himself testified that he never met with the lawyer outside the presence of Leroy. Again, we acknowledge that a lawyer meeting alone with one client, but not the other, in the context of a joint representation is worrisome. See id. at 859-860, 708 S.E.2d 279 (noting that, with one exception, lawyer never met with defendant outside the presence of the co-defendant or the family of the co-defendant).

The contentions about the manner in which the lawyer was paid and the way in which he communicated with his client depend, however, on the credibility of Leroy and Tolbert. The trial court did not expressly credit their testimony. There certainly were reasons to doubt their credibility,6 and more important, the "[c]redibility of witnesses and the weight to be given their testimony is is a decision-making power that lies solely with the trier of fact. The trier of fact is not obligated to believe a witness even if the testimony is uncontradicted and may accept or reject any portion of the testimony." Tate v. State, 264 Ga. 53, 56(3), 440 S.E.2d 646 (1994) (citation omitted). Our obligation to view the evidentiary record in the light most favorable to the findings and judgment of the trial court requires us to assume that the trial court in this case rejected the credibility of Tolbert and Leroy to the extent that their testimony is inconsistent with its decision. See Hughes v. State, 296 Ga. 744, 747(1), 770 S.E.2d 636 (2015). And in any event, even if Leroy alone paid the lawyer, and even if the lawyer met alone with Leroy (but not with Tolbert), the question would remain whether the potential conflict of interest for the lawyer had a significant and adverse effect on the way in which he represented Tolbert. See United States v. Wells, 394 F.3d 725, 734(III) (9th Cir.2005); Lipson v. United States, 233 F.3d 942, 946(II) (7th Cir.2000); Abernathy, 289 Ga. at 604(1), 715 S.E.2d 48; Blackshear, 274 Ga. at 844(2), 560 S.E.2d 688. We turn, therefore, to that question.

(c) According to Tolbert, Leroy was offered a favorable plea bargain at trial, but Tolbert was offered none, and this circumstance, he contends, shows that his lawyer prioritized the interests of Leroy over his own. This contention, however, relies on the testimony of Leroy that Leroy was, in fact, offered a plea bargain. Again, the trial court was not required to credit that testimony.7 Moreover, there is no evidence at all about what plea discussions the lawyer did or did not undertake on behalf of Tolbert — recall that the trial lawyer did not testify at the hearing on the motion for new trial. Cf. Ellis, 272 Ga. at 766(2), 534 S.E.2d 414 (evidence showed that lawyer obtained plea offers for both clients, but did not pursue a better bargain for one client that would involve his testifying against the other client, notwithstanding that evidence also showed that the State might well have bargained for such testimony). Likewise, there is no evidence that the prosecuting attorney would have been inclined to offer a favorable plea bargain to Tolbert, even if the lawyer had proposed that Tolbert would be willing to testify against Leroy. Cf. Burger, 483 U.S. at 785(III), 107 S.Ct. 3114 ("The notion that the prosecutor would have been receptive to a plea bargain is completely unsupported in the record."). Notably, Tolbert has failed to show that he could or would have given testimony against Leroy that would have been of meaningful value to the State at trial. To the contrary, at the hearing on the motion for new trial, Tolbert gave testimony that was largely exculpatory of Leroy. Consequently, there simply is no evidence that Tolbert would have been offered a favorable plea bargain, if only his lawyer had explored the possibility of Tolbert testifying against Leroy. See Christopher v. State, 262 Ga.App. 257, 263(3), 585 S.E.2d 107 (2003). See also Eisemann v. Herbert, 401 F.3d 102, 109-110(II)(3) (2nd Cir.2005). In addition, Tolbert has failed to show that the evidence would not support separate arguments for Tolbert and Leroy in plea negotiations, such that the lawyer could have negotiated pleas for Tolbert and Leroy alike without prejudicing either and without forcing the lawyer to choose one client over another. See People v. Tafoya, 833 P.2d 841, 845(III) (Colo.App. 1992). Even if we were to credit the testimony that Leroy gave below, the record is not developed sufficiently to permit us to assess whether the performance of the lawyer with respect to plea negotiations was adversely affected, much less significantly so, by his joint representation of Tolbert and Leroy. See State v. Smith, 748 So.2d 1139, 1142 (La.1999). For these reasons, Tolbert has failed to carry his burden to show that his lawyer did not seek a favorable plea bargain for Tolbert as the result of any conflict of interest.

(d) Finally, Tolbert contends that his lawyer could have argued at trial that Tolbert was less culpable than Leroy, but the lawyer did not, he says, because such an argument would only have focused the jury on the greater culpability of Leroy. In a case of joint representation of conflicting interests, the evil generally "is in what the advocate is compelled to refrain from doing. Thus, a failure on the part of counsel to pursue an alternative defense theory that is more favorable to one defendant but which would have prejudiced a co-defendant by shifting blame to him may well give rise to an actual conflict of interest." Mamedov, 288 Ga. at 861, 708 S.E.2d 279 (citation omitted).8 See also Abernathy, 289 Ga. at 605, 715 S.E.2d 48 ("[a] significant effect on the representation may be found, for example, where counsel is shown to have refrained from raising a potentially meritorious issue due to the conflict") (citation omitted); Meyers v. State, 265 Ga. 149, 150(2), 454 S.E.2d 490 (1995). That said, a mere failure to emphasize the different culpability of each co-defendant does not always and necessarily demonstrate an actual conflict. See Burger, 483 U.S. at 784(III), 107 S.Ct. 3114; Kegler v. State, 16 S.W.3d 908, 913 (Tex.App.2000). Accordingly, we now must consider whether the evidence adduced at trial would have, in fact, supported an argument that Tolbert was less culpable than Leroy,9 and we must consider as well whether the record shows that the failure of counsel to make such an argument is likely attributable to a conflicting loyalty that the lawyer owed to Leroy.

No doubt, some evidence was presented to the jury that might arguably suggest that Leroy was more culpable than Tolbert. That evidence includes proof of prior difficulties between Leroy and Tolbert, as well as evidence that Griffin threatened Leroy (believing him to be a "snitch"), that Tolbert backed off his initial threat to Griffin, and that Leroy told Dewey to "do it," leading to Dewey shooting Griffin. At the same time, however, some evidence presented at trial suggests that Tolbert was the more culpable of the two. Among other things, the evidence shows that Tolbert arrived on the scene with the eventual shooter, that Tolbert (but not Leroy) was carrying a gun, and that Tolbert directly threatened Griffin in the course of the confrontation. It is not clear, therefore, that any attempt to distinguish between the culpability of Tolbert and Leroy would have been helpful to Tolbert. In the light of that uncertainty, even if Tolbert and Leroy had been represented by separate counsel at trial, there would have been strategic reasons for those separate counsel not to advance arguments about differences in culpability between the two co-defendants. Accordingly, in the absence of any other evidence about what led the trial lawyer to choose another course, we cannot conclude that his failure to argue that Tolbert was less culpable than Leroy is indicative of an actual conflict of interest.

Moreover, we cannot say that an argument that Tolbert was less culpable than Leroy would have been significantly stronger than the common defense that the lawyer actually advanced at trial for Tolbert and Leroy, and for that reason as well, we cannot conclude that the failure to urge a defense based on comparative culpability likely was motivated by a conflict of interest. An alternative defense theory of differential culpability would have helped Tolbert only if it would have convinced the jury that Tolbert was so much less culpable that he — unlike Leroy — was not a party to the crime. See Ramirez v. Dretke, 396 F.3d 646, 650(II) (5th Cir. 2005). But notwithstanding any differences in his culpability and that of Leroy, the evidence that Tolbert was culpable enough to be a party to the crime was strong. The evidence shows, after all, that Tolbert arrived on the scene with a gun and accompanied by the eventual shooter, that Tolbert directly threatened Griffin, that Tolbert was linked by kinship to both Leroy and Dewey, that Tolbert fled the scene with Leroy and Dewey, and that Tolbert later went with Leroy and Dewey to the hospital in an attempt to confirm that Griffin was dead. See Teasley v. State, 288 Ga. 468, 469-470, 704 S.E.2d 800 (2011); Ashe v. State, 285 Ga. 359, 360-361(1), 676 S.E.2d 194 (2009); Scott v. State, 280 Ga. 466, 467(1), 629 S.E.2d 211 (2006).10

Rather than differentiating between Leroy and Tolbert, their lawyer argued at trial that Dewey had acted in self-defense when he shot Griffin (which was consistent with Dewey's own defense), and that even if Dewey were not justified, neither Leroy nor Tolbert was a party to the crime. In support of these defenses, the trial lawyer argued that both Leroy and Tolbert were just "standing there" at the scene of the crime, that neither pointed a gun at Griffin, that Griffin was a violent drug dealer who threatened Leroy and ultimately forced Dewey to defend himself, and that both Leroy and Tolbert were attempting to defuse the tense confrontation. As the United States Supreme Court has recognized, "[i]n many cases[,] a common defense gives strength against a common attack." Burger, 483 U.S. at 784(III), 107 S.Ct. 3114. See also Holloway v. Arkansas, 435 U.S. 475, 482(II), 98 S.Ct. 1173, 55 L.Ed.2d 426 (1978) ("[I]ndeed, in some cases, certain advantages might accrue from joint representation.... Joint representation is a means of insuring against reciprocal recrimination.") (punctuation omitted). The defenses of Tolbert and Leroy were perfectly compatible, as they both were based on the theory that Dewey had acted in self-defense and that, even if the evidence of self-defense failed, Tolbert and Leroy were not parties to the crime of murder. See State v. Smith, 748 So.2d 1139, 1144 (La.1999); Kegler, 16 S.W.3d at 913. The unified defense strategy was to show that both Tolbert and Leroy were innocent; neither of them testified, much less did one point the finger at the other. See Lamb, 267 Ga. at 42(1), 472 S.E.2d 683; Taylor v. State, 320 Ga.App. 596, 605(2), 740 S.E.2d 327 (2013); Mitchell v. State, 312 Ga.App. 293, 298(3), 718 S.E.2d 126 (2011). And there is no suggestion that urging this defense on behalf of Leroy somehow would have made the jury less likely to accept the same defense urged on behalf of Tolbert.

The contention that the failure of trial counsel to differentiate the culpability of Tolbert from that of Leroy is most probably explained by a conflict of interest is, at best, poorly supported. See State v. Newman, 928 P.2d 1040, 1045 (Utah App.1996). The trial court found "no evidence of anything that trial counsel could have done in defense of [Tolbert] that was not pursued out of a divided loyalty to codefendant Leroy Sims." Especially in the absence of any testimony from the trial lawyer, we cannot say that this finding is clearly erroneous. The record before us does not demonstrate that the choice of defense in this case was the result of a conflict of interest, as opposed to a reasonable strategic decision, an unreasonable strategic decision, or even inattention and neglect.11 The trial court was authorized to conclude that Tolbert failed to demonstrate that his lawyer's theoretical division of loyalties ripened into an actual conflict of interest that significantly and adversely affected the adequacy of the lawyer's representation of him at trial.

Judgment affirmed.

All the Justices concur.