Court Opinion

ID: 9959479
Source: CourtListenerOpinion
Date Created: 2024-04-11 19:01:05.840345+00
Date Added: 2024-06-11T08:18:19.618392
License: Public Domain

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                                                  [DO NOT PUBLISH]
                                    In the
                 United States Court of Appeals
                         For the Eleventh Circuit

                           ____________________

                                 No. 22-12331
                           ____________________

        ANDREW R. ALLRED,
                                                     Petitioner-Appellant,
        versus
        SECRETARY, FLORIDA DEPARTMENT OF CORRECTIONS,
        ATTORNEY GENERAL, STATE OF FLORIDA,

                                                  Respondents-Appellees.

                           ____________________

                  Appeal from the United States District Court
                       for the Middle District of Florida
                   D.C. Docket No. 6:16-cv-00560-PGB-LHP
                           ____________________
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        2                      Opinion of the Court                 22-12331

        Before JORDAN, JILL PRYOR, and BRASHER, Circuit Judges.
        PER CURIAM:
                Florida death-row prisoner Andrew Allred appeals the dis-
        trict court’s denial of his petition for a writ of habeas corpus under
        28 U.S.C. § 2254. This appeal concerns his claim that his trial coun-
        sel was constitutionally ineffective for failing to ensure that he un-
        derwent a reasonably competent mental health evaluation for use
        during the penalty phase of his criminal trial. After a thorough re-
        view of the record and with the benefit of oral argument, we affirm
        the district court’s denial of the ineffective assistance of counsel
        claim.
                                I.     BACKGROUND
                Allred pled guilty before a Florida court to two counts of
        first-degree murder as well as armed burglary, aggravated battery
        with a firearm, and criminal mischief. Because under Florida law
        his convictions made him eligible for the death penalty, he was en-
        titled to a penalty-phase trial to determine his sentence. See Fla.
        Stat. § 921.141(1). He waived his right to a jury during the penalty
        phase. Thus, a judge was tasked with weighing aggravating and
        mitigating factors to decide whether to sentence Allred to death or
        life imprisonment. See id. § 921.141(3)(b). The trial court sentenced
        Allred to death for both murders. After his death sentence was up-
        held on direct appeal, Allred pursued postconviction relief in the
        Florida state courts and then in federal court. Below we describe
        the evidence presented at Allred’s penalty-phase trial, his
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        22-12331               Opinion of the Court                          3

        sentencing, his state postconviction proceedings, and his federal ha-
        beas proceedings.
        A. The Penalty Phase
               After Allred pled guilty, his case proceeded directly to a pen-
        alty-phase bench trial. During the penalty phase, the State intro-
        duced evidence of the following facts.
               Allred had a romantic relationship with one of the two vic-
        tims in this case, Tiffany Barwick. Before her murder, Allred and
        Barwick were living together at Allred’s parents’ home. They
        ended their relationship with a fight on August 25, 2007. The fight
        and breakup happened at the Allred home during Allred’s 21st
        birthday party, which was attended by 50 guests. In attendance was
        Michael Ruschak, the other murder victim, who was Allred’s clos-
        est male friend at the time.
               Unable to cope with the breakup, Allred began harassing
        Barwick. Days after the breakup, he purchased a handgun. Imme-
        diately after obtaining the weapon, he used pictures of Barwick for
        target practice. He emailed her a photo of the bullet-riddled pic-
        tures, which hung on the wall of his room.
               After the breakup, Allred learned that Barwick and Ruschak
        had begun a sexual relationship. The day before the murders, he
        messaged his friend Michael Siler, “I pretty much just need to start
        killing people.” Allred v. State (Allred I), 55 So. 3d 1267, 1272 (Fla.
        2010). Siler replied, “[Y]ou’re just depressed.”
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        4                       Opinion of the Court                   22-12331

              The next day, Allred sent threatening messages to and about
        Barwick and Ruschak. In Allred’s direct appeal, the Florida Su-
        preme Court summarized the messages as follows:
               In an instant message chat with Siler in the morning,
               Allred stated, “I’m pretty much gonna kill him . . . Ru-
               schak . . . and her.” In an electronic conversation with
               victim Ruschak on that same day, Allred told him, “If
               [I] see you again, [I] will kill you, and yes that is a
               threat.” Finally, Allred and Barwick engaged in a
               heated and lengthy computer exchange on the day of
               the murder. Allred informed Barwick that he had
               hacked into her computer, changed the passwords,
               deleted ﬁles, and sent emails to people on her contacts
               list. He also transferred all of the funds in her bank
               account to pay her credit card debt. Calling her a
               “whore” because of her relationship with Ruschak,
               Allred said he could not forgive her for that and
               threatened, “[I]f [] I ever see [Ruschak] again I will kill
               him.”

        Allred I, 55 So. 3d at 1272–73 (alterations in original).
               That evening, Allred told Ruschak that he was coming over
        to Ruschak’s house. Allred took his handgun and drove to the
        home of Eric Roberts, where Ruschak lived and Barwick lived tem-
        porarily. Allred expected to find both Barwick and Ruschak at the
        house. Several guests who were acquainted with Allred were also
        at the house. Ruschak warned them of Allred’s impending arrival.
        According to one guest, Kathryn Cochran, when Barwick learned
        that Allred was coming over, she went into “panic mode.”
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        22-12331               Opinion of the Court                         5

                A few minutes after Ruschak’s announcement, Allred pulled
        up to the house. He repeatedly rammed his truck into Barwick’s
        car, which was parked outside. Guests inside the house heard the
        collisions. Cochran described hearing a noise like a mortar blast.
               Allred exited his truck and attempted to enter the home, but
        he was unable to enter because Ruschak had locked the front door
        in anticipation of his arrival. Allred banged loudly on the front
        door, yelling “[l]et me in,” but no one opened it. Allred I, 55 So. 3d
        at 1273.
               Allred then walked to back of the house and banged on a
        sliding glass door that opened to the living room, where some of
        the guests had gathered. Barwick ran away to hide. When no one
        let him in, Allred shot through the door. He walked through the
        broken glass into the house, gun in hand. The occupants scattered.
               Allred noticed Ruschak peering from the kitchen and pur-
        sued him, shooting him four times. Ruschak was killed instantly.
        Allred continued to the bathroom, where he found Barwick hiding
        in the bathtub. He shot her six times. She, too, died instantly. As
        Allred moved through the house, Roberts grabbed him, trying to
        stop him. Allred shot Roberts in the leg and escaped his grasp.
              Allred left the crime scene and drove home. He called 911
        and reported that he had killed two people. He threatened to com-
        mit suicide. When law enforcement officers arrived at Allred’s
        home, he was standing at the end of the driveway with a handgun
        on the ground next to him. He told his arresting officer, “I’m the
        guy you’re looking for.” Id. at 1274. After he was secured, Allred
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        6                         Opinion of the Court                      22-12331

        asked “if the people were dead,” and in the patrol car he said, “I
        knew I killed someone, I shot fourteen times.” Id.
                 After his arrest, detectives interviewed Allred about the
        murders. In the interview, he demanded to know “what happened
        to . . . the people that got shot” before confessing to shooting Ru-
        schak and Barwick. He confessed to the events of the shooting sub-
        stantially as described above. 1 He also confessed to using Barwick’s
        pictures for target practice. He told detectives that he killed Ru-
        schak because Ruschak was an “asshole” who sided with Barwick
        in the couple’s breakup. Id. at 1275. But Allred denied planning the
        murders, buying the gun to facilitate the murders, and going to
        Roberts’s house that night with the intent to shoot Barwick and
        Ruschak. He said that he drove to the scene only to ram Barwick’s
        car.
               Contrary to Allred’s denials, the State’s evidence indicated
        that the murders were premeditated. The State pointed to digital
        evidence of the threats he sent to and about Ruschak and Barwick
        leading up to the murders. Cochran, who had a conversation with
        Barwick about the threats at Roberts’s gathering, testified that Bar-
        wick was so “freaked out” about Allred’s communications that she
        called the police when she heard Allred was coming to the house.

        1 Although Allred described the events of the shooting in the police interview,
        in postconviction proceedings, his mental health expert, Dr. Glenn Caddy,
        opined that Allred’s reporting of the murders was imperfect or “fragmented.”
        We discuss Caddy’s opinion in more detail in Section B below.
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        22-12331               Opinion of the Court                        7

                The eyewitnesses who had been at Roberts’s home testified
        about Allred’s deliberate pursuit of Ruschak at the scene. They de-
        scribed Allred as singularly focused when, after shooting his way
        through the door, he silently moved past the guests in the living
        room to shoot Ruschak in the kitchen. Roberts testified to Allred’s
        cool affect during the murders, characterizing Allred’s tone of voice
        during their struggle as “somewhat calm” or “louder than calm.”
        Corroborating the eyewitness accounts, Allred confessed to detec-
        tives that he was “specifically looking for Michael” when he walked
        into Roberts’s kitchen.
                To prove that Barwick’s murder was especially heinous,
        atrocious, or cruel, an aggravating factor under state law, the State
        played the 911 call that Barwick made while hiding from Allred in
        the bathroom to illustrate the fear she experienced immediately be-
        fore her death. On the call, she screamed as she heard the gunshots
        that killed Ruschak and continued screaming as she was fatally shot
        moments later.
               For the defense in the penalty phase, Allred’s trial counsel,
        Timothy Caudill, called seven witnesses in mitigation, mostly
        Allred’s family members and former teachers. Caudill had difficulty
        organizing a mitigation case because Allred was sometimes unco-
        operative and generally reluctant to participate in mitigation ef-
        forts. Allred waived his right to be present and did not attend his
        penalty-phase trial.
               Caudill presented evidence that Allred was socially and emo-
        tionally developmentally delayed and that his family life was
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        8                      Opinion of the Court                  22-12331

        difficult. He argued that Allred’s developmental delays meant that
        he should be considered younger than 21 for sentencing purposes.
               The evidence about Allred’s developmental delays included
        testimony from his mother, Tora Allred, about his childhood. She
        noticed changes in Allred’s behavior beginning around the age of
        five or six, when he suddenly became hyper and emotional. Con-
        cerned about his behavior, Tora took him to a pediatrician who
        attributed his behavior to possible sexual abuse and referred him to
        a psychiatrist. The psychiatrist instead diagnosed Allred with a
        “well-defined tic disorder” (Allred licked his hand and rubbed his
        eye repetitively) and attention deficit hyperactivity disorder
        (“ADHD”). Id. The psychiatrist prescribed Allred medication to
        treat the ADHD.
               The pediatrician’s suggestion of sexual abuse was never sub-
        stantiated. Although there was alleged sexual abuse in Allred’s fam-
        ily—Allred’s older cousin filed a report that their grandfather and
        great uncle had sexually abused him—Allred never claimed to have
        been sexually abused. Allred’s grandfather testified that he and his
        grandson had a good relationship and that Allred had a good child-
        hood.
               But other testimony suggested that, in many ways, Allred
        had a troubled childhood, at school and home. Caudill argued that
        Allred’s developmental difficulties impacted his education and so-
        cial growth. To illustrate, Allred’s teachers testified that he did not
        interact with his peers or participate in class. His third-grade
        teacher testified that he was “withdrawn and ‘standoffish.’” Id. at
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        22-12331               Opinion of the Court                         9

        1276. Tora testified that around third grade, school progress re-
        ports suggested that her son might have a learning disability. Yet
        subsequent school testing revealed that Allred had a high IQ. As a
        result, he enrolled in gifted education classes in middle school. He
        did not adjust well to the program, however. Both Allred’s middle
        school teacher and Tora testified that he became even less social—
        more of a “loner”—throughout his middle school years. He even-
        tually stopped taking gifted classes.
               About Allred’s home life, his parents testified that he was ex-
        posed to alcohol abuse and domestic violence throughout child-
        hood. Allred’s father, David, and Tora agreed that David had an
        alcohol problem. They testified that they were physically violent
        toward each other. They described one violent incident involving
        Allred. One evening, David picked up a shotgun—Tora said he
        threatened to shoot himself; David said he was shooting at a tree
        to blow off steam—and assaulted Tora as she tried to take the
        weapon away. Allred, who was about 12 at the time, witnessed the
        assault and called the police. David was arrested. There was no tes-
        timony that Allred himself was abused.
               Despite Allred’s difficult childhood and developmental defi-
        cits, Tora admitted on cross-examination that by the time of the
        murders, her son was self-sufficient. Although he dropped out of
        high school in eleventh grade, he later earned his diploma and a
        two-year associate’s degree in accounting. Until the day of the mur-
        ders, when his employment was terminated, he worked full time,
        teaching the use of software. He lived independently in a large
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        10                       Opinion of the Court                     22-12331

        room, an addition to the family home that only he could access.
        For three or four months, Barwick lived there too, and, according
        to Tora, the couple was happy.
              Because of Allred’s emotional difficulty handling his
        breakup with Barwick, Caudill argued that Allred was suffering
        from extreme emotional disturbance at the time of the murders. In
        support, he presented Tora’s testimony that Allred became even
        more withdrawn after Barwick moved out. David testified that he
        was worried his son was suicidal after the breakup.
               Caudill’s arguments in the penalty phase about mitigating
        circumstances focused on Allred’s social and emotional develop-
        mental delays, difficult childhood, and emotional distress, yet he
        called no mental health expert to testify. Before trial, Caudill had
        identified Dr. Deborah Day, a psychologist, as a testifying expert.
        But Caudill decided not to call Day as a witness. 2
               After the penalty-phase trial concluded, the trial court sen-
        tenced Allred to death. The court found three statutory aggravat-
        ing factors for each murder. For Ruschak’s murder, the court con-
        cluded that (1) the murder was cold, calculated, and premeditated;
        (2) the murder was committed while Allred was engaged in a bur-
        glary; and (3) Allred had a prior capital conviction for Barwick’s
        contemporaneous murder. For Barwick’s murder, the court

        2 During postconviction proceedings, Caudill testified about his decision not
        to call Day. We discuss his testimony in Section B below.
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        22-12331                  Opinion of the Court                               11

        concluded that (1) the murder was especially heinous, atrocious, or
        cruel; (2) the murder was cold, calculated, and premeditated; and
        (3) Allred had a prior capital conviction for Ruschak’s contempora-
        neous murder. The court assigned great weight to all these aggra-
        vators except the contemporaneous burglary.
               The court found no statutory mitigating factors and four
        nonstatutory mitigating factors, all of which it assigned little or
        moderate weight. As nonstatutory mitigation, the court weighed
        the facts that Allred: (1) accepted responsibility by entering guilty
        pleas; (2) cooperated with law enforcement; (3) suffered from an
        emotional disturbance after his breakup with Barwick; and (4) had
        developmental problems at a young age that impacted his educa-
        tional and social development, but not his later education.3

        3 The court considered and rejected several other mitigating factors. It deter-
        mined that Allred’s emotional and developmental age at the time of the crime
        corresponded to his chronological age of 21 and therefore declined to weigh a
        younger emotional age as a mitigating circumstance. See Fla. Stat.
        § 921.141(7)(g) (identifying as a mitigating factor “the age of the defendant at
        the time of the crime”). And although the court recognized that Allred suf-
        fered from an emotional disturbance after the breakup, it did not apply the
        statutory mitigator for extreme emotional disturbance. See id. § 921.141(7)(b)
        (identifying as a mitigating factor that “[t]he capital felony was committed
        while the defendant was under the influence of extreme . . . emotional disturb-
        ance”). The court found that the “careful thought and planning of the mur-
        ders” negated such application. The court also stated that it was “not con-
        vinced that [Allred] was incapable of conforming his conduct to the require-
        ments of law.” See id. § 921.141(7)(f) (identifying as a mitigating factor that
        “[t]he capacity of the defendant to appreciate the criminality of his or her
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        12                        Opinion of the Court                     22-12331

               Weighing the aggravating and mitigating circumstances, the
        court found that the aggravating circumstances far outweighed the
        mitigating circumstances. The court sentenced Allred to death for
        the murders of both Ruschak and Barwick.
        B. State Postconviction Proceedings
                The Florida Supreme Court affirmed Allred’s death sentence
        on direct appeal. See Allred I, 55 So. 3d at 1284. Allred then initiated
        state postconviction proceedings, in which, as relevant here, he
        claimed that Caudill, his penalty-phase trial counsel, rendered con-
        stitutionally ineffective assistance under Strickland v. Washington,
        466 U.S. 668 (1984), by failing to ensure that he received a reasona-
        bly competent mental health evaluation. 4 Allred alleged that Cau-
        dill performed deficiently in three respects. First, he alleged that
        Caudill unreasonably relied on the opinion of Day, the mental
        health expert Caudill retained. Allred alleged that Caudill mistak-
        enly believed Day would testify that Allred had antisocial person-
        ality disorder, sociopathy, or psychopathy and relied on this under-
        standing in deciding to withdraw her testimony in the penalty
        phase. Second, Allred alleged that Caudill failed to conduct an ade-
        quate background investigation and therefore failed to adequately
        prepare Day. Third, Allred alleged that Caudill failed to present the

        conduct or to conform his or her conduct to the requirements of law was sub-
        stantially impaired”).
        4 In postconviction proceedings, Allred raised other challenges to his convic-
        tions and sentence. We limit our discussion to Allred’s ineffective assistance
        claim regarding the mental health evaluation, the only claim in this appeal.
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        22-12331               Opinion of the Court                         13

        testimony of a mental health expert as mitigation in the penalty
        phase. Allred alleged that Caudill was obligated to pursue other ex-
        perts, specifically those that were “tailored to the needs of the case”
        and had expertise with Allred’s developmental issues.
               This deficient performance, Allred alleged, prejudiced his
        case such that had counsel performed effectively, there was a rea-
        sonable probability that he would not have received a death sen-
        tence. See Strickland, 466 U.S. at 687 (explaining that, to establish
        ineffective assistance of counsel, the defendant “must show that
        counsel’s performance was deficient” and “that the deficient per-
        formance prejudiced the defense”).
                      1. The Postconviction Evidentiary Hearing
               The postconviction trial court conducted an evidentiary
        hearing on several of Allred’s claims, including the claim relevant
        here: that Caudill rendered ineffective assistance by failing to en-
        sure that Allred underwent a reasonably competent mental health
        evaluation for use in the penalty phase. At the hearing, Allred’s
        postconviction counsel introduced two types of mental health evi-
        dence that Allred contended supported his theories of deficient per-
        formance. First, counsel introduced evidence of possibly mitigating
        mental health conditions—dissociation and autism spectrum disor-
        der—that Allred argued Caudill should have developed. Second,
        counsel introduced evidence to undermine Day’s purported diag-
        nosis of antisocial personality disorder, a potentially aggravating
        mental health condition.
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        14                      Opinion of the Court                  22-12331

               Allred’s counsel called two licensed psychologists. Both eval-
        uated Allred in preparation for the evidentiary hearing. The first
        psychologist, Dr. Glenn Caddy, testified that Allred was in a disso-
        ciative state during the murders. This meant that Allred was “dis-
        connect[ed] from a clear understanding” of his actions. Caddy
        opined that the dissociative state was triggered by Allred’s pro-
        found “ego disintegration”—his sense of degradation and emo-
        tional distress—following his public breakup with Barwick and the
        discovery that she was involved with Ruschak. Caddy opined that,
        because of the dissociation and Allred’s deteriorating emotional
        state, Allred satisfied a statutory mitigator: he had diminished ca-
        pacity at the time of the crime. See Fla. Stat. § 921.141(7)(f) (listing
        as a mitigating factor that “[t]he capacity of the defendant to appre-
        ciate the criminality of his or her conduct or to conform his or her
        conduct to the requirements of law was substantially impaired”).
                Caddy testified that Allred’s postconviction reporting of the
        murders showed a fragmented memory of what happened inside
        Roberts’s house. In Caddy’s opinion, Allred’s postarrest interview
        indicated fragmentation. To Caddy, the disconnect between
        Allred’s behavior and his inability to explain it indicated dissocia-
        tion. But Caddy conceded on cross-examination that a fragmented
        memory could also have been Allred’s response to the trauma of
        the shootings. He agreed it was possible that Allred’s memory frag-
        mented under the stress of the violence he inflicted rather than be-
        cause of dissociation before the shootings. Thus, Caddy could not
        say whether the symptoms of dissociation he observed actually
        “set[] the stage” for the shooting.
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        22-12331               Opinion of the Court                        15

                Allred’s postconviction counsel also called Dr. Gary Ge-
        ffken, an autism specialist, who opined that Allred had a high-func-
        tioning form of autism spectrum disorder or “at the very least[,]
        pervasive developmental disorder.” Geffken based his opinion on
        social and emotional deficiencies he observed upon meeting Allred
        and assessing his background. Geffken opined that Allred was emo-
        tionally underdeveloped: he lacked sympathy, empathy, and the
        ability to discuss emotions like jealousy or embarrassment. Geffken
        also opined that Allred was socially underdeveloped. When Ge-
        ffken met with Allred, he found him to be intentionally solitary,
        cutting himself off from human interaction. Records established
        that Allred had also been this way in childhood and had difficulties
        interacting with peers. In Geffken’s opinion, Allred also exhibited
        other characteristics of autism spectrum disorder: Allred adapted
        poorly to change and had exhibited unusual repetitive behaviors
        and tics in childhood.
                Geffken concluded that Allred’s autism was a plausible ex-
        planation for why he murdered Ruschak and Barwick. Geffken pos-
        ited that when Allred and Barwick broke up, Allred was unable to
        cope with the loss because he did not have the social and emotional
        skills of a normal adult his age. Allred’s actions stemmed from this
        inability to process his emotions. Geffken opined that the for-
        mation of intense, consuming attachments—and an inability to
        cope with their loss—was characteristic of behavior across the au-
        tism spectrum. But Geffken acknowledged on cross-examination
        that the type of violence Allred carried out was “clearly” atypical of
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        16                     Opinion of the Court                 22-12331

        those on the autism spectrum. Geffken unequivocally stated that
        Allred was not remorseful and that his actions had been deliberate.
               But Caddy thought that Allred had recently demonstrated
        an “intellectual” remorse for what he had done. Anticipating the
        testimony of the State’s witnesses, including withdrawn penalty-
        phase mental health expert Day, Caddy unequivocally opined that
        Allred did not have antisocial personality disorder. Allred did not
        meet the diagnostic criteria for antisocial personality disorder be-
        cause he had no history of a childhood conduct disorder. And
        Caddy observed that Allred showed no history of failing to corre-
        spond to social norms and noted that before the murders he had
        no history of getting into significant trouble. Caddy concluded that
        Allred displayed empathy that was contraindicative of antisocial
        personality disorder.
                Postconviction counsel then called Allred’s trial counsel,
        Caudill, attempting to show that Caudill unreasonably relied on
        this contraindicated diagnosis of antisocial personality disorder to
        justify his decision to not present a mental health expert in the pen-
        alty phase. Caudill’s reliance on Day’s purported antisocial person-
        ality disorder diagnosis, postconviction counsel argued, prevented
        him from adequately investigating more favorable mental health
        diagnoses like dissociation and autism spectrum disorder.
               Caudill testified to his understanding of Day’s evaluation of
        Allred, their conversations about her potential testimony as to an-
        tisocial personality disorder and other aggravators, and his decision
        not to call Day or another mental health expert. He testified that
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        22-12331                 Opinion of the Court                            17

        he retained Day as a mental health expert before the penalty phase.
        After Day evaluated Allred, in the time leading up to the trial, Cau-
        dill had multiple conversations with her about her evaluation. Dur-
        ing one of these conversations, Day relayed that she had nothing
        to offer in mitigation in Allred’s case. Caudill understood from the
        conversation that if Day testified and had to offer a diagnosis, the
        only diagnosis she could offer would be antisocial personality dis-
        order—or worse, that Allred was a psychopath or sociopath. Put
        differently, her findings were consistent with a diagnosis of antiso-
        cial personality disorder. 5 And though Caudill understood that an
        antisocial personality disorder diagnosis must be premised on a
        childhood conduct disorder, he believed there was evidence of
        such a disorder in Allred’s past, such that an antisocial personality
        disorder diagnosis was not contraindicated.
                According to Caudill, in his experience, antisocial personal-
        ity disorder, sociopathy, and psychopathy were not mitigating. He
        further believed that calling Day, or any mental health expert,
        would elicit damaging testimony on Allred’s reporting of the mur-
        ders. Caudill viewed Allred’s explanation for the murders—that the
        victims were deserving—as aggravating. He also thought that men-
        tal health expert testimony as to Allred’s animosity toward the

        5 A contemporaneous memo written by Caudill’s cocounsel stated that Day
        had “concluded that Mr. Allred is a sociopath or psychopath.” This statement
        was not accurate, however. Day never diagnosed Allred. Both the postconvic-
        tion trial court and the Florida Supreme Court determined that despite the
        memo’s overstatement of Day’s conclusion, Caudill did not misunderstand
        her evaluation. The record does not contradict this finding of fact.
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        18                     Opinion of the Court                22-12331

        victims, expressed in Allred’s own words, would be more impactful
        than the State’s comparable evidence. For all these reasons, he de-
        cided to withdraw Day as a testifying witness.
               Caudill testified that he never had cause to question Day’s
        conclusions, nor did he consider seeking a second opinion or ex-
        pert. He did not believe that another expert would have come to a
        different conclusion or been able to provide mental health mitiga-
        tion. He was also concerned about delaying the penalty phase to
        pursue other experts, given Allred’s hostility toward developing a
        mitigation case.
               The State called Day at the postconviction hearing. Through
        Day, the State aimed to establish that Caudill had correctly con-
        cluded that Day’s expert testimony would have been more aggra-
        vating than mitigating. Therefore, the State argued, Caudill made
        a reasonable strategic decision to forgo the presentation of mental
        health evidence in the penalty phase.
                Day testified that, at Caudill’s behest she, along with two
        psychologists in her employ, had conducted a comprehensive eval-
        uation of Allred before his penalty-phase trial. Based on her evalu-
        ation, Day opined at the postconviction hearing that Allred had
        “features” of antisocial personality disorder: he met some, but not
        all, of the criteria for the disorder described in the Diagnostic and
        Statistical Manual of Mental Disorders. She determined that Allred
        displayed an inability to have empathy, had interpersonal difficul-
        ties, had difficulties obeying societal norms, and evidenced a reck-
        less disregard for others. But she also concluded that he did not
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        22-12331                   Opinion of the Court                                19

        have a childhood or adolescent conduct disorder; she saw evidence
        of antisocial traits emerging only past the age of 15. Because such a
        conduct disorder is a required criterion for a diagnosis of antisocial
        personality disorder, Day could not formally diagnose him.
                According to Day, Allred demonstrated features of psychop-
        athy, which she described as a “descriptor[] of behavior” rather
        than a separate diagnosis. She opined that many of Allred’s antiso-
        cial traits—deceptiveness, irresponsibility, poor behavioral control,
        lack of empathy, and disregard for others—were also characteristic
        of psychopathy. Allred’s clinically elevated scores on the psycho-
        pathic deviate scale of a personality test she administered, the Min-
        nesota Multiphasic Personality Inventory 2 (“MMPI-2”), were con-
        sistent with her impressions. 6
               Day testified consistently with Caudill’s impressions of her
        conclusions. If she had testified at the penalty phase, she said, her
        testimony would have been aggravating rather than mitigating.
        She could offer little in the way of statutory mitigation, and her
        opinions would have supported aggravators, including that the
        murders were cold, calculated, and premeditated. She opined that
        Allred’s behavior leading up to the murders evidenced premedita-
        tion and observed that he displayed a lack of remorse.

        6 Day also testified that Allred had clinically elevated scores for depression and
        trauma. She did not explain how those scores related to her impressions of
        Allred’s traits, background, or behavior, though she did report that Allred ex-
        perienced situational depression in jail.
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        20                        Opinion of the Court                       22-12331

               The State called a second mental health expert, psychiatrist
        Dr. Jeffrey Danziger, who evaluated Allred and reviewed the other
        experts’ conclusions. 7 Danziger refuted Caddy’s diagnosis of disso-
        ciation and Geffken’s diagnosis of autism spectrum disorder.
               Like Caddy, Danziger opined that Allred did not have anti-
        social personality disorder. Aside from the murders and the sur-
        rounding events, Danziger found that Allred lacked traits that
        would support an antisocial personality disorder diagnosis. But he
        “agree[d] wholeheartedly” with Day’s evaluation and postconvic-
        tion testimony and opined that, accounting for the murders, Allred
        displayed features of the disorder. Danziger also agreed with Caddy
        and Day that Allred would not meet the criteria for a “full-scale
        diagnosis” of antisocial personality disorder, in part because he had
        no conduct disorder before the age of 15. Danziger saw no perva-
        sive pattern of criminal conduct in Allred’s behavior. He opined
        that Allred was not a sociopath or a psychopath.
               Danziger disagreed entirely with Caddy’s finding that Allred
        was in a dissociative emotional state during the murders. He
        opined that the evidence of Allred’s actions surrounding the mur-
        ders suggested premeditation rather than confusion, disorienta-
        tion, or a lack of control. He characterized Allred’s imperfect

        7 Danziger had met previously with Allred, at Caudill’s request, shortly after
        Allred’s arrest in 2007. There was conflicting testimony as to whether this pre-
        trial evaluation was intended to evaluate Allred’s competency only or also to
        assess the possibility of an insanity defense. Danziger met with Allred again in
        2013 to evaluate him at the State’s behest.
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        22-12331               Opinion of the Court                        21

        memory as “a very thin reading to base a diagnosis of dissociative
        disorder on.”
               Danziger also disagreed with Geffken’s diagnosis of autism
        spectrum disorder. Although Danziger believed that Allred had so-
        cial deficits, he explained that to be diagnosed with autism spec-
        trum disorder, a person must have a restrictive repetitive pattern
        of behavior, interest, or activities. He did not find that Allred pre-
        sented such a pattern, though he failed to consider Allred’s child-
        hood tic disorder when making this conclusion. Danziger further
        opined that an autism spectrum disorder diagnosis would not be
        mitigating even if correct. If Allred were autistic, he still would
        have been able to appreciate the wrongfulness of his conduct and
        conform his conduct to law. And Danziger saw no evidence that
        Allred was experiencing extreme emotional distress.
              Danziger summarized that had he testified at trial, he could
        not have offered any testimony in mitigation other than the evi-
        dence that had been offered in the penalty phase. He noted the ev-
        idence of Allred’s exposure to domestic violence and his historic
        diagnoses of ADHD and tic disorder, but the court had acknowl-
        edged those facts at sentencing.
                   2. The State Postconviction Trial Court’s Order
              The postconviction trial court denied Allred’s claim that trial
        counsel rendered constitutionally ineffective assistance in failing to
        ensure that Allred received a reasonably competent mental health
        evaluation. It concluded that Allred failed to show that Caudill
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        22                     Opinion of the Court                  22-12331

        performed deficiently or that any deficiency prejudiced him. See
        Strickland, 466 U.S. at 687.
               The postconviction trial court assessed Caudill’s perfor-
        mance as to each of the three deficiencies Allred alleged: that Cau-
        dill unreasonably relied on Day’s antisocial personality disorder di-
        agnosis, that Caudill failed to conduct an adequate background in-
        vestigation, and that Caudill failed to seek out additional mental
        health experts to testify in the penalty phase.
               First, the court concluded that Caudill reasonably relied on
        his understanding of Day’s opinion. Caudill correctly understood
        that “Day had not diagnosed the Defendant with anti-social per-
        sonality disorder, but rather, she indicated that if she was forced to
        give a diagnosis the only diagnosis she could offer was anti-social
        personality disorder.” State v. Allred, No. 07-4890, 2013 WL
        12450438, at *3 (Fla. Cir. Ct. 2013).
              Second, the court concluded Allred offered no evidence that
        Caudill conducted an inadequate background investigation or in-
        adequately prepared Day. Allred’s argument to the contrary had
        no support.
                Consequently, Caudill was entitled to rely on Day’s opinion.
        Given Day’s opinion that Allred had antisocial traits and her indi-
        cation that she could not provide helpful testimony, the court con-
        cluded that Caudill’s choice not to present Day’s testimony was a
        “reasonable strategic decision” rather than deficient performance.
        Id. at *4. It was also a “successful” decision in that it precluded the
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        22-12331               Opinion of the Court                         23

        introduction of additional damaging evidence as to Allred’s pre-
        meditation and lack of remorse. Id.
               Because the court concluded that Caudill’s reliance on Day’s
        opinion was reasonable, it followed that he “was not required to
        continue searching for an expert who would give a more favorable
        assessment of [Allred’s] mental status.” Id. (internal quotation
        marks omitted). The court therefore rejected Allred’s third argu-
        ment, that Caudill was obligated to seek another mental health ex-
        pert to testify at the penalty phase, concluding that Caudill’s failure
        to do so did not amount to deficient performance.
               Despite finding no deficient performance, the postconvic-
        tion trial court proceeded to analyze whether Caudill’s failure to
        present a mental health expert prejudiced Allred. The court looked
        to whether the new mental health evidence adduced in postconvic-
        tion—the diagnoses provided by Caddy and Geffken—would have
        altered the sentencing outcome. The court found the testimony of
        both experts not credible.
               It found that Caddy’s diagnosis of dissociation at the time of
        the murders was unsupported, in part, because the diagnosis relied
        on Allred’s “alleged fragmented memory” of the murders, yet
        Caddy “acknowledged that the Defendant’s fragmented memory
        could be the result of a physiological reaction to the trauma of the
        shooting.” Id. at *5. And the court credited Danziger’s contrary
        opinion that there was no evidence of Allred’s having been in a dis-
        sociative state.
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        24                      Opinion of the Court                  22-12331

               The court also found not credible Geffken’s testimony that
        Allred had autism spectrum disorder. It credited Danziger’s testi-
        mony that, to be diagnosed with autism spectrum disorder, one
        must display a restrictive repetitive pattern of behavior. It found a
        “lack of evidence” that Allred had restrictive repetitive behavior
        patterns. Id.
                Because it found Caddy’s and Geffken’s testimony not cred-
        ible and credited Danziger’s, the court concluded that Allred failed
        to establish that he was in a dissociative state at the time of the
        murders or that he had autism spectrum disorder. But even if
        Allred had credibly demonstrated those diagnoses, the court found,
        their introduction would not have impacted the penalty phase’s
        outcome because his experts’ testimony failed to show that Allred’s
        capacity was, in fact, diminished, and that he lacked premeditated
        intent.
                       3. The Florida Supreme Court’s Decision
                The Florida Supreme Court affirmed the postconviction
        trial court’s denial of Allred’s ineffective assistance claim. Allred v.
        State (Allred II), 186 So. 3d 530, 539 (Fla. 2016). It ruled that Allred
        “demonstrated neither deficiency nor prejudice” as to Caudill’s fail-
        ure to obtain a competent mental health evaluation during the pen-
        alty phase. Id. at 539.
               Like the postconviction trial court, the Florida Supreme
        Court evaluated Caudill’s performance as to each of the three defi-
        ciencies that Allred alleged. First, the court concluded that Caudill
        reasonably relied on Day’s opinion. Id. at 536–37. It held that Day
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        22-12331               Opinion of the Court                       25

        had “clearly indicated,” and Caudill correctly understood, “that her
        testimony would be more aggravating than mitigating.” Id. at 537.
        Although Day “did not reach the [antisocial personality disorder]
        diagnosis, her testimony that Allred met all but one of the factors
        essential to the diagnosis would not have been mitigating in nature.
        Neither would her testimony that he had some of the traits of a
        sociopath and a psychopath.” Id. Further, by withdrawing Day’s
        testimony, “Caudill kept out testimony about Allred’s lack of em-
        pathy or remorse.” Id. His reliance on her “professional assess-
        ment” was not unreasonable, and his decision to withdraw her tes-
        timony was a reasonable strategic choice. Id.
                Second, the court concluded that Caudill’s background in-
        vestigation was not deficient. Id. at 537–38. It determined that Cau-
        dill conducted an adequate background investigation to prepare his
        mitigation case in the penalty phase; the court cited his efforts to
        track down records, witnesses, and evidence that Allred was possi-
        bly sexually abused by his grandfather. Id. at 538.
               Third, the Florida Supreme Court determined that Caudill’s
        decision not to call Day “did not require the continued search for a
        more favorable mental health opinion.” Id. Caudill’s failure to find
        and present a favorable mental health expert in the penalty phase
        did not constitute deficient performance. Id. In addition, Caddy and
        Geffken were not credible, and the evidence presented at the post-
        conviction hearing “established neither that [Allred] was in a disso-
        ciative state nor that he suffered from an autism spectrum disor-
        der.” Id. at 538–39. Thus, Allred failed to present evidence of a
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        26                      Opinion of the Court                    22-12331

        favorable opinion. But even if he had, the court stated that “secur-
        ing a more favorable expert opinion” would not “undermine the
        sufficiency” of Day’s opinion, on which Caudill was entitled to rely.
        Id. at 539.
        C. Federal Habeas Proceedings
                Allred then filed a petition for a writ of habeas corpus in fed-
        eral district court, raising several claims, including a claim that trial
        counsel rendered ineffective assistance by failing to obtain a rea-
        sonably competent mental health evaluation. The district court de-
        nied Allred relief and then denied him a certificate of appealability.
        We granted Allred a certificate of appealability on his claim that
        trial counsel was constitutionally ineffective in two ways, for failing
        to (1) conduct a sufficient background investigation and (2) ensure
        a reasonably competent mental health evaluation for Allred’s pen-
        alty phase.
                          II.     STANDARDS OF REVIEW
                “When reviewing a district court’s grant or denial of habeas
        relief, we review questions of law and mixed questions of law and
        fact de novo, and findings of fact for clear error.” Reaves v. Sec’y, Fla.
        Dep’t of Corr., 717 F.3d 886, 899 (11th Cir. 2013) (internal quotation
        marks omitted). An ineffective assistance of counsel claim “pre-
        sents a mixed question of law and fact that we review de novo.” Pope
        v. Sec’y, Fla. Dep’t of Corr., 752 F.3d 1254, 1261 (11th Cir. 2014).
             The Antiterrorism and Effective Death Penalty Act of 1996
        (“AEDPA”) governs our review of federal habeas petitions.
        “AEDPA prescribes a highly deferential framework for evaluating
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        22-12331               Opinion of the Court                         27

        issues previously decided in state court.” Sears v. Warden GDCP,
        73 F.4th 1269, 1279 (11th Cir. 2023). AEDPA bars federal courts
        from granting habeas relief to a petitioner on a claim that was “ad-
        judicated on the merits in [s]tate court” unless the decision (1) “was
        contrary to, or involved an unreasonable application of, clearly es-
        tablished Federal law, as determined by the Supreme Court of the
        United States,” or (2) “was based on an unreasonable determina-
        tion of the facts in light of the evidence presented in the [s]tate
        court proceeding.” 28 U.S.C. § 2254(d).
                A state-court decision is “contrary to” clearly established law
        if the court “applie[d] a rule that contradicts the governing law” set
        forth by the Supreme Court or the state court confronted facts that
        were “materially indistinguishable” from Supreme Court prece-
        dent but arrived at a different result. Williams v. Taylor, 529 U.S.
        362, 405–06 (2000). To meet the “unreasonable application” stand-
        ard, “a prisoner must show far more than that the state court’s de-
        cision was merely wrong or even clear error.” Shinn v. Kayer, 592
        U.S. 111, 118 (2020) (internal quotation marks omitted). Rather, the
        decision must be “so obviously wrong that its error lies beyond any
        possibility for fair minded disagreement.” Id. (internal quotation
        marks omitted). This standard is “difficult to meet and . . . demands
        that state-court decisions be given the benefit of the doubt.”
        Raulerson v. Warden, 928 F.3d 987, 996 (11th Cir. 2019) (internal
        quotation marks omitted).
              A federal habeas court must defer to a state court’s determi-
        nation of the facts unless the state court decision “was based on an
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        28                     Opinion of the Court                 22-12331

        unreasonable determination of the facts in light of the evidence
        presented in the [s]tate court proceeding.” 28 U.S.C. § 2254(d)(2).
        We are required to give state courts “substantial deference” under
        § 2254(d)(2). Brumfield v. Cain, 576 U.S. 305, 314 (2015). “We may
        not characterize . . . state-court factual determinations as unreason-
        able merely because we would have reached a different conclusion
        in the first instance.” Id. at 313–14 (alteration adopted) (internal
        quotation marks omitted). We presume a state court’s factual de-
        terminations are correct absent clear and convincing evidence to
        the contrary. See Pye v. Warden, Ga. Diagnostic Prison, 50 F.4th 1025,
        1035 (11th Cir. 2022) (en banc).
               On each claimed basis for relief, we review “the last state-
        court adjudication on the merits.” See Greene v. Fisher, 565 U.S. 34,
        40 (2011). “When a federal claim has been presented to a state court
        and the state court has denied relief,” we presume “the state court
        adjudicated the claim on the merits in the absence of any indication
        or state-law procedural principles to the contrary.” Harrington v.
        Richter, 562 U.S. 86, 99 (2011). Allred’s relevant ineffective assis-
        tance claim was adjudicated on the merits, and thus we review it
        under AEDPA’s standards.
                                 III.   DISCUSSION
              In this appeal, Allred argues that his trial counsel was consti-
        tutionally ineffective for failing to ensure a reasonably competent
        mental health evaluation during the penalty phase, as he did in
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        22-12331                   Opinion of the Court                               29

        state postconviction proceedings.8 He argues that Caudill’s failure
        to present mental health evidence was deficient in two ways.
                First, Allred argues that Caudill unreasonably relied on a
        misunderstanding of Day’s evaluation of Allred’s mental state with-
        out adequate investigation into her opinion. This led Caudill to
        provide ineffective assistance of counsel by deciding not to call
        Day, or another mental health expert, in the penalty phase. Allred
        contends that Caudill erroneously understood Day’s opinion to be
        that if “she had to diagnose Mr. Allred, she would state that he suf-
        fered from Antisocial Personality Disorder (ASPD), sociopathy, or
        psychopathy.” Appellant’s Br. 9. According to Allred, Caudill was
        required to second-guess this opinion and investigate the supposed
        diagnosis of antisocial personality disorder further. Had he done so,
        Allred contends, Day would have continued her work and offered
        the “firm conclusion” that Allred did not have antisocial personality
        disorder due to his lack of adolescent conduct disorder. Reply Br.

        8 As noted above, we granted a certificate of appealability on two aspects of
        Allred’s ineffective assistance of counsel claim: that trial counsel was ineffec-
        tive for failing to (1) conduct a sufficient background investigation and (2) en-
        sure a reasonably competent mental health evaluation for the penalty phase.
        Allred’s argument on appeal, however, addresses only (2), counsel’s failure to
        ensure a reasonably competent mental health evaluation. He does not argue
        that Caudill performed a deficient background investigation; instead, he now
        argues that Caudill failed to investigate the basis of Day’s evaluation and opin-
        ion, which is simply another way of saying that Caudill unreasonably relied
        on Day’s opinion in deciding not to call her as a witness. We therefore discuss
        only the claim that Caudill was ineffective in failing to ensure Allred under-
        went a reasonably competent mental health evaluation for the penalty phase.
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        30                     Opinion of the Court                 22-12331

        4–6. Because Caudill did not question Day’s evaluation, Allred ar-
        gues, his decision to withdraw her testimony was based on insuffi-
        cient investigation and thus constituted deficient performance.
                Second, Allred argues that Caudill performed deficiently by
        failing to seek out and present the testimony of additional mental
        health professionals, like Caddy and Geffken, whose testimony
        would have supported statutory mental health mitigators in the
        penalty phase. Had the trial court heard the testimony of a mental
        health expert, Allred says, there is a reasonable probability that it
        would have weighed the balance of aggravating and mitigating cir-
        cumstances in his favor and sentenced him to life imprisonment
        instead of death.
               Counsel provides ineffective assistance, warranting vacatur
        of a conviction or sentence, when his performance falls “below an
        objective standard of reasonableness,” taking into account prevail-
        ing professional norms, and “there is a reasonable probability that,
        but for counsel’s unprofessional errors, the result of the proceeding
        would have been different.” Strickland, 466 U.S. at 688, 694. “A rea-
        sonable probability is a probability sufficient to undermine confi-
        dence in the outcome.” Id. at 694. To determine whether this rea-
        sonable probability exists, “we consider the totality of the available
        mitigation evidence—both that adduced at trial, and the evidence
        adduced in the habeas proceeding—and reweigh it against the evi-
        dence in aggravation.” Porter v. McCollum, 558 U.S. 30, 41 (2009) (al-
        teration adopted) (internal quotation marks omitted). When apply-
        ing AEDPA to this prejudice standard, “we must decide whether
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        22-12331                   Opinion of the Court                               31

        the state court’s conclusion that [counsel’s] performance . . . didn’t
        prejudice [the petitioner]—that there was no substantial likelihood
        of a different result—was so obviously wrong that its error lies be-
        yond any possibility for fairminded disagreement.” Pye, 50 F.4th at
        1041–42 (internal quotation marks omitted).
                We conclude that the Florida Supreme Court’s determina-
        tion that Allred was not prejudiced by his counsel’s failure to pre-
        sent the testimony of a mental health expert during the penalty
        phase was not unreasonable, and thus its decision is entitled to def-
        erence under AEDPA.9 Because Allred failed to establish prejudice
        under the Strickland-AEDPA framework, we affirm the federal dis-
        trict court’s denial of habeas relief. In so ruling, we need not address
        whether the Florida Supreme Court’s conclusions as to trial coun-
        sel’s deficient performance were reasonable. “Because a petitioner
        must prove both deficient performance and prejudice, a court need
        not address one element if it determines that the petitioner has
        failed to prove the other.” Mashburn v. Comm’r, Ala. Dep’t of Corr.,
        80 F.4th 1292, 1301 (11th Cir. 2023) (internal quotation marks omit-
        ted).

        9 The Florida Supreme Court said little regarding the prejudice prong of
        Allred’s claim. Nonetheless, it concluded that Allred “failed to establish either
        prong of Strickland” as to each of his ineffective assistance claims and, more
        particularly, ruled that Allred “demonstrated neither deficiency nor prejudice”
        as to the claim that Caudill rendered ineffective assistance in failing to ensure
        that Allred underwent a reasonably competent mental health evaluation for
        the penalty phase. Allred II, 186 So. 3d at 535, 539.
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        32                      Opinion of the Court                    22-12331

                Allred resists our conclusion. In arguing that he was preju-
        diced by trial counsel’s performance, he relies on the testimony of
        Caddy and Geffken. He argues that his experts’ opinions on two
        diagnoses—dissociation and autism spectrum disorder—show that
        the statutory “mental health” mitigators applied to him. Appel-
        lant’s Br. 20; see Fla. Stat. § 921.141(7)(b), (h). Therefore, he argues,
        his experts would have shifted the balance of aggravating and mit-
        igating factors and created a reasonable probability of a life sen-
        tence. But at the postconviction hearing the parties introduced con-
        flicting evidence as to whether Allred experienced dissociation and
        whether he met the criteria to be diagnosed with autism spectrum
        disorder. The State’s expert, Danziger, refuted Caddy’s and Ge-
        ffken’s diagnoses. The state postconviction trial court resolved the
        factual disputes by crediting Danziger’s opinion over the opinions
        of Allred’s experts, and the Florida Supreme Court affirmed that
        finding.
                We first consider whether the credibility finding—a deter-
        mination of fact, Jones v. Sec’y, Fla. Dep’t of Corr., 834 F.3d 1299, 1315
        (11th Cir. 2016)—was unreasonable. See Pye, 50 F.4th at 1035–36
        (stating that we cannot grant habeas relief unless the state court’s
        “ultimate decision” was “based on an unreasonable determination
        of the facts in light of the evidence presented in the State court pro-
        ceeding” (internal quotation marks omitted)). Allred argues that
        the court made “an unreasonable interpretation of the facts [and]
        the testimony” on its way to concluding that “neither Dr. Caddy’s
        nor Dr. Geffken’s testimony would have changed the outcome” of
        his penalty phase, because “[b]oth experts were able to show that
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        22-12331                Opinion of the Court                         33

        the mental health statutory mitigator applied.” Appellant’s Br. 19–
        20. Thus, Allred asks us to evaluate the prejudice prong of his inef-
        fective assistance claim based on the testimony of his experts and
        “not based on which expert the courts found more convincing.” Id.
        at 23. In so arguing, Allred asks us to reject the finding that Caddy
        and Geffken were not credible and to credit their opinions over the
        contrary opinion of the State’s expert, Danziger. We cannot do so.
        We have held that it is not unreasonable for a state habeas court to
        discount the testimony of one expert in favor of another’s when
        the experts’ testimony conflicts, so long as crediting the opposing
        expert’s testimony is itself not unreasonable. See Ferguson v. Sec’y,
        Fla. Dep’t of Corr., 716 F.3d 1315, 1340–41 (11th Cir. 2013); Jones, 834
        F.3d at 1316–17; Pye, 50 F.4th at 1050. Allred does not argue that
        crediting Danziger’s testimony was unreasonable. So we cannot
        say that it was unreasonable for the Florida Supreme Court to af-
        firm the state postconviction trial court’s finding that Allred’s ex-
        perts were not credible.
               We next consider the Florida Supreme Court’s ruling that
        Allred failed to establish the prejudice prong of his ineffective assis-
        tance of counsel claim. The prejudice ruling is a legal conclusion
        that we review under § 2254(d)(1). We conclude that the court’s
        determination was neither “contrary to,” nor “an unreasonable ap-
        plication of, clearly established federal law” under the statute. 28
        U.S.C. § 2254(d)(1). In deciding whether the ruling was unreasona-
        ble, we reweigh the evidence in mitigation against the evidence in
        aggravation. Porter, 558 U.S. at 41. And so we turn back to the evi-
        dence introduced at the evidentiary hearing.
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        34                     Opinion of the Court                 22-12331

               Without Caddy’s and Geffken’s opinions, the mental health
        evidence adduced at the hearing yielded little in mitigation. The
        only other testimony indicating that Allred had significant mental
        health conditions came from Day, who testified that Allred had fea-
        tures of antisocial personality disorder and psychopathy. In a case
        where a habeas petitioner presented with “antisocial tendencies,”
        this Court said that evidence of antisocial personality disorder is
        “not mitigating, but damaging.” Suggs v. McNeil, 609 F.3d 1218,
        1231 (11th Cir. 2010) (internal quotation marks omitted). More re-
        cently, we have observed that high psychopathic deviate scores on
        the MMPI-2 and testimony to behavior consistent with that score
        are damaging rather than mitigating. Puiatti v. Sec’y, Fla. Dep’t. of
        Corr., 732 F.3d 1255, 1288–89 (11th Cir. 2019). And so, here, as in
        Suggs, Day’s testimony “would have come at a steep price.” Suggs,
        609 F.3d at 1231.
               We acknowledge that at the hearing experts on both sides
        noted social and familial difficulties in Allred’s background, as well
        as his childhood mental health diagnoses of ADHD and tic disor-
        der. But these facts were presented during the penalty-phase trial
        and considered at sentencing. In addition, at sentencing the trial
        court weighed Allred’s emotional distress following his breakup
        with Barwick. Thus, Geffken’s and Caddy’s testimony on the emo-
        tional trauma they believed Allred suffered post-breakup—even di-
        vorced from these experts’ discredited diagnoses—was of little ad-
        ditional mitigating value. Because the evidence presented in state
        habeas proceedings was “by no means clearly mitigating” or other-
        wise “largely duplicated” mitigation evidence at trial, we cannot
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        22-12331                Opinion of the Court                         35

        say that it was unreasonable for the Florida Supreme Court to con-
        clude that Allred had failed to show a substantial likelihood of a
        different sentence. See Cullen v. Pinholster, 563 U.S. 170, 200–01
        (2011).
                Our conclusion that the Florida Supreme Court’s no-preju-
        dice determination was based a reasonable application of Strickland
        is bolstered by the strength of the aggravating circumstances the
        sentencing court identified. Where there is “substantial evidence of
        aggravating circumstances,” it is more difficult for a petitioner to
        establish prejudice under Strickland. Holsey v. Warden, Ga. Diagnos-
        tic Prison, 694 F.3d 1230, 1269 (11th Cir. 2012). So, too, when the
        mitigating evidence is scant. The new mitigating evidence in this
        case—that Allred had antisocial traits—would likely have been
        damaging. Even considering the mitigating evidence presented at
        trial—that Allred had social difficulties, a troubled family life, and
        childhood developmental disorders but was a self-sufficient young
        adult with no prior history of violence—we cannot conclude that
        the Florida Supreme Court unreasonably found no prejudice, given
        the aggravating circumstances.
                And “[t]his is not a case where the weight of the aggravating
        circumstances or the evidence supporting them was weak.” Sochor
        v. Sec’y, Dep’t of Corr., 685 F.3d 1016, 1030 (11th Cir. 2012) (internal
        quotation marks omitted). The trial court found that both Ru-
        schak’s and Barwick’s murders were cold, calculated, and
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        36                        Opinion of the Court                      22-12331

        premeditated and that Barwick’s murder was heinous, atrocious,
        or cruel.10
                For the cold, calculated, and premeditated aggravator, the
        evidence of premeditation in the penalty-phase case was strong.
        The trial court cited the timing of Allred’s purchase of the murder
        weapon, his threatening messages to and about the victims, and his
        warning to Ruschak about his arrival at the scene as evidence that
        the murders were preplanned. If Caddy’s testimony had been cred-
        ited, it is possible that his opinion of Allred’s diminished capacity
        might have mitigated the impact of this premeditation evidence.
        But Caddy’s testimony was not credited. And Allred introduced no
        other evidence at the evidentiary hearing to undercut the cold, cal-
        culated, and premeditated aggravator. To the contrary, the evi-
        dence adduced at the evidentiary hearing tended to show that the
        testimony of a mental health expert would have supported the
        cold, calculated, and premeditated aggravator. Based on her evalu-
        ation of Allred, Day opined that his behavior leading up to the

        10 As we previously noted, the court found additional aggravating factors as
        to each murder. As to Ruschak’s murder, the court found aggravating that
        Allred committed the murder while engaged in a burglary, and he was previ-
        ously convicted of another capital felony (Barwick’s contemporaneous mur-
        der). As to Barwick’s murder, the court found aggravating that Allred was pre-
        viously convicted of another capital felony (Ruschak’s contemporaneous mur-
        der). Because the cold, calculated, and premeditated and heinous, atrocious,
        or cruel findings are sufficient to support our conclusion that the Florida Su-
        preme Court’s prejudice determination was not unreasonable, we do not dis-
        cuss the court’s findings as to the other aggravators.
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        22-12331               Opinion of the Court                        37

        murders suggested premeditation. Caddy testified that Allred had
        a preconceived fantasy of killing Ruschak and Barwick.
                To support the heinous, atrocious, or cruel aggravator, the
        trial court adduced from the 911 call Barwick made while hiding
        from Allred that she was terror-stricken, anticipating her own
        death, in the minutes before Allred shot and killed her. It described
        the 911 call “as the most horrific piece of evidence this court has
        heard in a homicide case in nearly twenty-three years as a trial
        judge.” And the heinous, atrocious, or cruel aggravator “pertains
        more to the nature of the killing and the surrounding circum-
        stances” than the petitioner’s mental state. Hardwick v. Sec’y, Fla.
        Dep’t of Corr., 803 F.3d 541, 561 (11th Cir. 2015) (internal quotation
        marks omitted). Thus, postconviction testimony about Allred’s
        mental state was unlikely to undermine the heinous, atrocious, or
        cruel aggravator.
                We have said that the cold, calculated, premeditated and
        heinous, atrocious, or cruel aggravators are “among the most seri-
        ous aggravating circumstances.” Id. at 559. It is improbable that the
        evidence adduced at Allred’s postconviction evidentiary hearing
        would have reduced the impact of these powerful aggravators suf-
        ficiently to introduce the reasonable probability of a different out-
        come for Allred. See Pye, 50 F.4th at 1049 (“We’ve repeatedly held
        that even extensive mitigating evidence wouldn’t have been rea-
        sonably likely to change the outcome of sentencing in light of a
        particularly heinous crime and significant aggravating factors.”).
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        38                     Opinion of the Court                 22-12331

                For these reasons, the Florida Supreme Court’s determina-
        tion that Allred could not show prejudice from his trial counsel’s
        performance withstands our highly deferential review under
        AEDPA. The court’s ruling that there was no substantial likelihood
        of a life sentence in Allred’s case was not “so obviously wrong that
        its error lies beyond any possibility for fairminded disagreement,”
        so it is entitled to deference. See id. at 1041–42 (internal quotation
        marks omitted). Our reweighing of the totality of the evidence in
        mitigation against the evidence in aggravation shows that Allred
        was unable to shift the balance of the sentencing factors. Although
        Allred argues that evidence of his mental state should have been
        presented at trial, the mental health evidence adduced at the post-
        conviction hearing—notwithstanding the testimony found not
        credible—would have been of little value. The mental health ex-
        pert testimony presented was either supportive of existing aggra-
        vating factors like premeditation, supportive of new and poten-
        tially aggravating mental health diagnoses like antisocial personal-
        ity disorder, or cumulative of mitigating evidence the sentencing
        court considered. We therefore cannot say that the Florida Su-
        preme Court’s prejudice ruling was “contrary to” or “an unreason-
        able application of[] clearly established Federal law.” 28 U.S.C.
        § 2254(d)(1). The court’s decision withstands our highly deferential
        review under AEDPA, and we affirm the denial of relief on Allred’s
        penalty phase ineffective assistance of counsel claim.
                                IV.    CONCLUSION
              The district court’s denial of Allred’s petition for a writ of
        habeas corpus is AFFIRMED.