Task: sc_lcdispositiondirection

What follows is an opinion from the Supreme Court of the United States. Your task is to determine whether the decision of the court whose decision the Supreme Court reviewed was itself liberal or conservative. In the context of issues pertaining to criminal procedure, civil rights, First Amendment, due process, privacy, and attorneys, consider liberal to be pro-person accused or convicted of crime, or denied a jury trial, pro-civil liberties or civil rights claimant, especially those exercising less protected civil rights (e.g., homosexuality), pro-child or juvenile, pro-indigent pro-Indian, pro-affirmative action, pro-neutrality in establishment clause cases, pro-female in abortion, pro-underdog, anti-slavery, incorporation of foreign territories anti-government in the context of due process, except for takings clause cases where a pro-government, anti-owner vote is considered liberal except in criminal forfeiture cases or those where the taking is pro-business violation of due process by exercising jurisdiction over nonresident, pro-attorney or governmental official in non-liability cases, pro-accountability and/or anti-corruption in campaign spending pro-privacy vis-a-vis the 1st Amendment where the privacy invaded is that of mental incompetents, pro-disclosure in Freedom of Information Act issues except for employment and student records. In the context of issues pertaining to unions and economic activity, consider liberal to be pro-union except in union antitrust where liberal = pro-competition, pro-government, anti-business anti-employer, pro-competition, pro-injured person, pro-indigent, pro-small business vis-a-vis large business pro-state/anti-business in state tax cases, pro-debtor, pro-bankrupt, pro-Indian, pro-environmental protection, pro-economic underdog pro-consumer, pro-accountability in governmental corruption, pro-original grantee, purchaser, or occupant in state and territorial land claims anti-union member or employee vis-a-vis union, anti-union in union antitrust, anti-union in union or closed shop, pro-trial in arbitration. In the context of issues pertaining to judicial power, consider liberal to be pro-exercise of judicial power, pro-judicial "activism", pro-judicial review of administrative action. In the context of issues pertaining to federalism, consider liberal to be pro-federal power, pro-executive power in executive/congressional disputes, anti-state. In the context of issues pertaining to federal taxation, consider liberal to be pro-United States and conservative pro-taxpayer. In miscellaneous, consider conservative the incorporation of foreign territories and executive authority vis-a-vis congress or the states or judcial authority vis-a-vis state or federal legislative authority, and consider liberal legislative veto. The lower court's decision direction is unspecifiable if the manner in which the Supreme Court took jurisdiction is original or certification; or if the direction of the Supreme Court's decision is unspecifiable and the main issue pertains to private law or interstate relations

Justice Souter
delivered the opinion of the Court.
After his first trial in 1984 ended in a hung jury, petitioner Curtis Lee Kyles was tried again, convicted of first-degree murder, and sentenced to death. On habeas review, we follow the established rule that the state’s obligation under Brady v. Maryland, 373 U. S. 83 (1963), to disclose evidence favorable to the defense, turns on the cumulative effect of all such evidence suppressed by the government, and we hold that the prosecutor remains responsible for gauging that effect regardless of any failure by the police to bring favorable evidence to the prosecutor’s attention. Because the net effect of the evidence withheld by the State in this case raises a reasonable probability that its disclosure would have produced a different result, Kyles is entitled to a new trial.
I
Following the mistrial when the jury was unable to reach a verdict, Kyles’s subsequent conviction and sentence of death were affirmed on direct appeal. State v. Kyles, 513 So. 2d 265 (La. 1987), cert. denied, 486 U. S. 1027 (1988). On state collateral review, the trial court denied relief, but the Supreme Court of Louisiana remanded for an evidentiary hearing on Kyles’s claims of newly discovered evidence. During this state-court proceeding, the defense was first able to present certain evidence, favorable to Kyles, that the State had failed to disclose before or during trial. The state trial court nevertheless denied relief, and the State Supreme Court denied Kyles’s application for discretionary review. State ex rel. Kyles v. Butler, 566 So. 2d 386 (La. 1990).
Kyles then filed a petition for habeas corpus in the United States District Court for the Eastern District of Louisiana, which denied the petition. The Court of Appeals for the Fifth Circuit affirmed by a divided vote. 5 F. 3d 806 (1993). As we explain, infra, at 440-441, there is reason to question whether the Court of Appeals evaluated the significance of undisclosed evidence under the correct standard. Because “[o]ur duty to search for constitutional error with painstaking care is never more exacting than it is in a capital case,” Burger v. Kemp, 483 U. S. 776, 785 (1987), we granted certiorari, 511 U. S. 1051 (1994), and now reverse.
II
A
The record indicates that, at about 2:20 p.m. on Thursday, September 20, 1984, 60-year-old Dolores Dye left the Schwegmann Brothers’ store (Schwegmann’s) on Old Gentilly Road in New Orleans after doing some food shopping. As she put her grocery bags into the trunk of her red Ford LTD, a man accosted her and after a short struggle drew a revolver, fired into her left temple, and killed her. The gunman took Dye’s keys and drove away in the LTD.
New Orleans police took statements from six eyewitnesses, who offered various descriptions of the gunman. They agreed that he was a black man, and four of them said that he had braided hair. The witnesses differed significantly, however, in their descriptions of height, age, weight, build, and hair length. Two reported seeing a man of 17 or 18, while another described the gunman as looking as old as 28. One witness described him as 5'4" or 5'5", medium build, 140-150 pounds; another described the man as slim and close to six feet. One witness said he had a mustache; none of the others spoke of any facial hair at all. One witness said the murderer had shoulder-length hair; another described the hair as “short.”
Since the police believed the killer might have driven his own car to Schwegmann’s and left it there when he drove off in Dye’s LTD, they recorded the license numbers of the cars remaining in the parking lots around the store at 9:15 p.m. on the evening of the murder. Matching these numbers with registration records produced the names and addresses of the owners of the cars, with a notation of any owner’s police record. Despite this list and the eyewitness descriptions, the police had no lead to the gunman until the Saturday evening after the shooting.
At 5:30 p.m., on September 22, a man identifying himself as James Joseph called the police and reported that on the day of the murder he had bought a red Thunderbird from a friend named Curtis, whom he later identified as petitioner, Curtis Kyles. He said that he had subsequently read about Dye’s murder in the newspapers and feared that the car he purchased was the victim’s. He agreed to meet with the police.
A few hours later, the informant met New Orleans Detective John Miller, who was wired with a hidden body microphone, through which the ensuing conversation was recorded. See App. 221-257 (transcript). The informant now said his name was Joseph Banks and that he was called Beanie. His actual name was Joseph Wallace.
His story, as well as his name, had changed since his earlier call. In place of his original account of buying a Thunderbird from Kyles on Thursday, Beanie told Miller that he had not seen Kyles at all on Thursday, id., at 249-250, and had bought a red LTD the previous day, Friday, id., at 221-222, 225. Beanie led Miller to the parking lot of a nearby bar, where he had left the red LTD, later identified as Dye’s.
Beanie told Miller that he lived with Kyles’s brother-in-law (later identified as Johnny Burns), whom Beanie repeatedly called his “partner.” Id., at 221. Beanie described Kyles as slim, about 6-feet tall, 24 or 25 years old, with a “bush” hairstyle. Id., at 226, 252. When asked if Kyles ever wore his hair in plaits, Beanie said that he did but that he “had a bush” when Beanie bought the car. Id., at 249.
During the conversation, Beanie repeatedly expressed concern that he might himself be a suspect in the murder. He explained that he had been seen driving Dye’s car on Friday evening in the French Quarter, admitted that he had changed its license plates, and worried that he “could have been charged” with the murder on the basis of his possession of the LTD. Id., at 231, 246, 250. He asked if he would be put in jail. Id., at 235, 246. Miller acknowledged that Beanie’s possession of the car would have looked suspicious, id., at 247, but reassured him that he “didn’t do anything wrong,” id., at 235.
Beanie seemed eager to cast suspicion on Kyles, who allegedly made his living by “robbing people,” and had tried to kill Beanie at some prior time. Id., at 228, 245, 251. Beanie said that Kyles regularly carried two pistols, a.38 and a.32, and that if the police could “set him up good,” they could “get that same gun” used to kill Dye. Id., at 228-229. Beanie rode with Miller and Miller’s supervisor, Sgt. James Eaton, in an unmarked squad car to Desire Street, where he pointed out the building containing Kyles’s apartment. Id., at 244-246.
Beanie told the officers that after he bought the car, he and his “partner” (Burns) drove Kyles to Schwegmann’s about 9 p.m. on Friday evening to pick up Kyles’s car, described as an orange four-door Ford. Id., at 221, 223, 231-232, 242. When asked where Kyles’s car had been parked, Beanie replied that it had been “[o]n the same side [of the lot] where the woman was killed at.” Id., at 231. The officers later drove Beanie to Schwegmann’s, where he indicated the space where he claimed Kyles’s car had been parked. Beanie went on to say that when he and Burns had brought Kyles to pick up the car, Kyles had gone to some nearby bushes to retrieve a brown purse, id., at 253-255, which Kyles subsequently hid in a wardrobe at his apartment. Beanie said that Kyles had “a lot of groceries” in Schwegmann’s bags and a new baby’s potty “in the car.” Id., at 254-255. Beanie told Eaton that Kyles’s garbage would go out the next day and that if Kyles was “smart” he would “put [the purse] in [the] garbage.” Id., at 257. Beanie made it clear that he expected some reward for his help, saying at one point that he was not “doing all of this for nothing.” Id., at 246. The police repeatedly assured Beanie that he would not lose the $400 he paid for the car. Id., at 243, 246.
After the visit to Schwegmann’s, Eaton and Miller took Beanie to a police station where Miller interviewed him again on the record, which was transcribed and signed by Beanie, using his alias “Joseph Banks.” See id., at 214-220. This statement, Beanie’s third (the telephone call being the first, then the recorded conversation), repeats some of the essentials of the second one: that Beanie had purchased a red Ford LTD from Kyles for $400 on Friday evening; that Kyles had his hair “combed out” at the time of the sale; and that Kyles carried a.32 and a.38 with him “all the time.”
Portions of the third statement, however, embellished or contradicted Beanie’s preceding story and were even internally inconsistent. Beanie reported that after the sale, he and Kyles unloaded Schwegmann’s grocery bags from the trunk and back seat of the LTD and placed them in Kyles’s own car. Beanie said that Kyles took a brown purse from the front seat of the LTD and that they then drove in separate cars to Kyles’s apartment, where they unloaded the groceries. Id., at 216-217. Beanie also claimed that, a few hours later, he and his “partner” Burns went with Kyles to Schwegmann’s, where they recovered Kyles’s car and a “big brown pocket book” from “next to a building.” Id., at 218. Beanie did not explain how Kyles could have picked up his car and recovered the purse at Schwegmann’s, after Beanie had seen Kyles with both just a few hours earlier. The police neither noted the inconsistencies nor questioned Beanie about them.
Although the police did not thereafter put Kyles under surveillance, Tr. 94 (Dec. 6, 1984), they learned about events at his apartment from Beanie, who went there twice on Sunday. According to a fourth statement by Beanie, this one given to the chief prosecutor in November (between the first and second trials), he first went to the apartment about 2 p.m., after a telephone conversation with a police officer who asked whether Kyles had the gun that was used to kill Dye. Beanie stayed in Kyles’s apartment until about 5 p.m., when he left to call Detective John Miller. Then he returned about 7 p.m. and stayed until about 9:30 p.m., when he left to meet Miller, who also asked about the gun. According to this fourth statement, Beanie “rode around” with Miller until 3 a.m. on Monday, September 24. Sometime during those same early morning hours, detectives were sent at Sgt. Eaton’s behest to pick up the rubbish outside Kyles’s building. As Sgt. Eaton wrote in an interoffice memorandum, he had “reason to believe the victims [sic] personal papers and the Schwegmann’s bags will be in the trash.” Record, Defendant’s Exh. 17.
At 10:40 a.m., Kyles was arrested as he left the apartment, which was then searched under a warrant. Behind the kitchen stove, the police found a.32-caliber revolver containing five live rounds and one spent cartridge. Ballistics tests later showed that this pistol was used to murder Dye. In a wardrobe in a hallway leading to the kitchen, the officers found a homemade shoulder holster that fit the murder weapon. In a bedroom dresser drawer, they discovered two boxes of ammunition, one containing several.32-caliber rounds of the same brand as those found in the pistol. Back in the kitchen, various cans of cat and dog food, some of them of the brands Dye typically purchased, were found in Schwegmann’s sacks. No other groceries were identified as possibly being Dye’s, and no potty was found. Later that afternoon at the police station, police opened the rubbish bags and found the victim’s purse, identification, and other personal belongings wrapped in a Schwegmann’s sack.
The gun, the LTD, the purse, and the cans of pet food were dusted for fingerprints. The gun had been wiped clean. Several prints were found on the purse and on the LTD, but none was identified as Kyles’s. Dye’s prints were not found on any of the cans of pet food. Kyles's prints were found, however, on a small piece of paper taken from the front passenger-side floorboard of the LTD. The crime laboratory recorded the paper as a Schwegmann’s sales slip, but without noting what had been printed on it, which was obliterated in the chemical process of lifting the fingerprints. A second Schwegmann’s receipt was found in the trunk of the LTD, but Kyles’s prints were not found on it. Beanie’s fingerprints were not compared to any of the fingerprints found. Tr. 97 (Dec. 6, 1984).
The lead detective on the case, John Dillman, put together a photo lineup that included a photograph of Kyles (but not of Beanie) and showed the array to five of the six eyewitnesses who had given statements. Three of them picked the photograph of Kyles; the other two could not confidently identify Kyles as Dye’s assailant.
B
Kyles was indicted for first-degree murder. Before trial, his counsel filed a lengthy motion for disclosure by the State of any exculpatory or impeachment evidence. The prosecution responded that there was “no exculpatory evidence of any nature,” despite the government’s knowledge of the following evidentiary items: (1) the six contemporaneous eyewitness statements taken by police following the murder; (2) records of Beanie’s initial call to the police; (3) the tape recording of the Saturday conversation between Beanie and officers Eaton and Miller; (4) the typed and signed statement given by Beanie on Sunday morning; (5) the computer printout of license numbers of cars parked at Schwegmann’s on the night of the murder, which did not list the number of Kyles’s car; (6) the internal police memorandum calling for the seizure of the rubbish after Beanie had suggested that the purse might be found there; and (7) evidence linking Beanie to other crimes at Schwegmann’s and to the unrelated murder of one Patricia Leidenheimer, committed in January before the Dye murder.
At the first trial, in November, the heart of the State’s case was eyewitness testimony from four people who were at the scene of the crime (three of whom had previously picked Kyles from the photo lineup). Kyles maintained his innocence, offered supporting witnesses, and supplied an alibi that he had been picking up his children from school at the time of the murder. The theory of the defense was that Kyles had been framed by Beanie, who had planted evidence in Kyles’s apartment and his rubbish for the purposes of shifting suspicion away from himself, removing an impediment to romance with Pinky Burns, and obtaining reward money. Beanie did not testify as a witness for either the defense or the prosecution.
Because the State withheld evidence, its case was much stronger, and the defense case much weaker, than the full facts would have suggested. Even so, after four hours of deliberation, the jury became deadlocked on the issue of guilt, and a mistrial was declared.
After the mistrial, the chief trial prosecutor, Cliff Strider, interviewed Beanie. See App. 258-262 (notes of interview). Strider’s notes show that Beanie again changed important elements of his story. He said that he went with Kyles to retrieve Kyles’s car from the Schwegmann’s lot on Thursday, the day of the murder, at some time between 5 and 7:30 p.m., not on Friday, at 9 p.m., as he had said in his second and third statements. (Indeed, in his second statement, Beanie said that he had not seen Kyles at all on Thursday. Id., at 249-250.) He also said, for the first time, that when they had picked up the car they were accompanied not only by Johnny Burns but also by Kevin Black, who had testified for the defense at the first trial. Beanie now claimed that after getting Kyles’s car they went to Black's house, retrieved a number of bags of groceries, a child’s potty, and a brown purse, all of which they took to Kyles’s apartment. Beanie also stated that on the Sunday after the murder he had been at Kyles’s apartment two separate times. Notwithstanding the many inconsistencies and variations among Beanie’s statements, neither Strider’s notes nor any of the other notes and transcripts were given to the defense.
In December 1984, Kyles was tried a second time. Again, the heart of the State’s case was the testimony of four eyewitnesses who positively identified Kyles in front of the jury. The prosecution also offered a blown-up photograph taken at the crime scene soon after the murder, on the basis of which the prosecutors argued that a seemingly two-toned car in the background of the photograph was Kyles’s. They repeatedly suggested during cross-examination of defense witnesses that Kyles had left his own car at Schwegmann’s on the day of the murder and had retrieved it later, a theory for which they offered no evidence beyond the blown-up photograph. Once again, Beanie did not testify.
As in the first trial, the defense contended that the eyewitnesses were mistaken. Kyles’s counsel called several individuals, including Kevin Black, who testified to seeing Beanie, with his hair in plaits, driving a red car similar to the victim’s about an hour after the killing. Tr. 209 (Dec. 7, 1984). Another witness testified that Beanie, with his hair in braids, had tried to sell him the car on Thursday evening, shortly after the murder. Id., at 234-235. Another witness testified that Beanie, with his hair in a “Jheri curl,” had attempted to sell him the car on Friday. Id., at 249-251. One witness, Beanie’s “partner,” Burns, testified that he had seen Beanie on Sunday at Kyles’s apartment, stooping down near the stove where the gun was eventually found, and the defense presented testimony that Beanie was romantically interested in Pinky Burns. To explain the pet food found in Kyles’s apartment, there was testimony that Kyles’s family kept a dog and cat and often fed stray animals in the neighborhood.
Finally, Kyles again took the stand. Denying any involvement in the shooting, he explained his fingerprints on the cash register receipt found in Dye’s car by saying that Beanie had picked him up in a red car on Friday, September 21, and had taken him to Schwegmann’s, where he purchased transmission fluid and a pack of cigarettes. He suggested that the receipt may have fallen from the bag when he removed the cigarettes.
On rebuttal, the prosecutor had Beanie brought into the courtroom. All of the testifying eyewitnesses, after viewing Beanie standing next to Kyles, reaffirmed their previous identifications of Kyles as the murderer. Kyles was convicted of first-degree murder and sentenced to death. Beanie received a total of $1,600 in reward money. See Tr. of Hearing on Post-Conviction Relief 19-20 (Feb. 24, 1989); id., at 114 (Feb. 20, 1989).
Following direct appeal, it was revealed in the course of state collateral review that the State had failed to disclose evidence favorable to the defense. After exhausting state remedies, Kyles sought relief on federal habeas, claiming, among other things, that the evidence withheld was material to his defense and that his conviction was thus obtained in violation of Brady. Although the United States District Court denied relief and the Fifth Circuit affirmed, Judge King dissented, writing that “[f]or the first time in my fourteen years on this court... I have serious reservations about whether the State has sentenced to death the right man.” 5 F. 3d, at 820.
Ill
The prosecution’s affirmative duty to disclose evidence favorable to a defendant can trace its origins to early 20th-century strictures against misrepresentation and is of course most prominently associated with this Court’s decision in Brady v. Maryland, 373 U. S. 83 (1963). See id., at 86 (relying on Mooney v. Holohan, 294 U. S. 103, 112 (1935), and Pyle v. Kansas, 317 U. S. 213, 215-216 (1942)). Brady held “that the suppression by the prosecution of evidence favorable to an accused upon request violates due process where the evidence is material either to guilt or to punishment, irrespective of the good faith or bad faith of the prosecution.” 373 U. S., at 87; see Moore v. Illinois, 408 U. S. 786, 794-795 (1972). In United States v. Agurs, 427 U. S. 97 (1976), however, it became clear that a defendant’s failure to request favorable evidence did not leave the Government free of all obligation. There, the Court distinguished three situations in which a Brady claim might arise: first, where previously undisclosed evidence revealed that the prosecution introduced trial testimony that it knew or should have known was perjured, 427 U. S., at 103-104; second, where the Government failed to accede to a defense request for disclosure of some specific kind of exculpatory evidence, id., at 104-107; and third, where the Government failed to volunteer exculpatory evidence never requested, or requested only in a general way. The Court found a duty on the part of the Government even in this last situation, though only when suppression of the evidence would be “of sufficient significance to result in the denial of the defendant’s right to a fair trial.” Id., at 108.
In the third prominent case on the way to current Brady law, United States v. Bagley, 473 U. S. 667 (1985), the Court disavowed any difference between exculpatory and impeachment evidence for Brady purposes, and it abandoned the distinction between the second and third Agurs circumstances, i. e., the “specific-request”'and “general- or no-request” situations. Bagley held that regardless of request, favorable evidence is material, and constitutional error results from its suppression by the government, “if there is a reasonable probability that, had the evidence been disclosed to the defense, the result of the proceeding would have been different.” 473 U. S., at 682 (opinion of Blackmun, J.); id., at 685 (White, J., concurring in part and concurring in judgment).
Four aspects of materiality under Bagley bear emphasis. Although the constitutional duty is triggered by the potential impact of favorable but undisclosed evidence, a showing of materiality does not require demonstration by a preponderance that disclosure of the suppressed evidence would have resulted ultimately in the defendant’s acquittal (whether based on the presence of reasonable doubt or acceptance of an explanation for the crime that does not inculpate the defendant). Id., at 682 (opinion of Blackmun, J.) (adopting formulation announced in Strickland v. Washington, 466 U. S. 668, 694 (1984)); Bagley, supra, at 685 (White, J., concurring in part and concurring in judgment) (same); see 473 U. S., at 680 (opinion of Blackmun, J.) (Agurs “rejected a standard that would require the defendant to demonstrate that the evidence if disclosed probably would have resulted in acquittal”); cf. Strickland, supra, at 693 (“[W]e believe that a defendant need not show that counsel’s deficient conduct more likely than not altered the outcome in the case”); Nix v. Whiteside, 475 U. S. 157, 175 (1986) (“[A] defendant need not establish that the attorney’s deficient performance more likely than not altered the outcome in order to establish prejudice under Strickland”). Bagley’s touchstone of materiality is a “reasonable probability” of a different result, and the adjective is important. The question is not whether the defendant would more likely than not have received a different verdict with the evidence, but whether in its absence he received a fair trial, understood as a trial resulting in a verdict worthy of confidence. A “reasonable probability” of a different result is accordingly shown when the government’s evidentiary suppression “undermines confidence in the outcome of the trial.” Bagley, 473 U. S., at 678.
The second aspect of Bagley materiality bearing emphasis here is that it is not a sufficiency of evidence test. A defendant need not demonstrate that after discounting the inculpatory evidence in light of the undisclosed evidence, there would not have been enough left to convict. The possibility of an acquittal on a criminal charge does not imply an insufficient evidentiary basis to convict. One does not show a Brady violation by demonstrating that some of the inculpatory evidence should have been excluded, but by showing that the favorable evidence could reasonably be taken to put the whole case in such a different light as to undermine confidence in the verdict.
Third, we note that, contrary to the assumption made by the Court of Appeals, 5 F. 3d, at 818, once a reviewing court applying Bagley has found constitutional error there is no need for further harmless-error review. Assuming, arguendo, that a harmless-error enquiry were to apply, a Bagley error could not be treated as harmless, since “a reasonable probability that, had the evidence been disclosed to the defense, the result of the proceeding would have been different,” 473 U. S., at 682 (opinion of Blackmun, J.); id., at 685 (White, J., concurring in part and concurring in judgment), necessarily entails the conclusion that the suppression must have had “‘substantial and injurious effect or influence in determining the jury’s verdict,’ ” Brecht v. Abrahamson, 507 U. S. 619, 623 (1993), quoting Kotteakos v. United States, 328 U. S. 750, 776 (1946). This is amply confirmed by the development of the respective governing standards. Although Chapman v. California, 386 U. S. 18, 24 (1967), held that a conviction tainted by constitutional error must be set aside unless the error complained of “was harmless beyond a reasonable doubt,” we held in Brecht that the standard of harmlessness generally to be applied in habeas cases is the Kotteakos formulation (previously applicable only in reviewing nonconstitutional errors on direct appeal), Brecht, supra, at 622-623. Under Kotteakos a conviction may be set aside only if the error “had substantial and injurious effect or influence in determining the jury’s verdict.” Kotteakos, supra, at 776. Agurs, however, had previously rejected Kotteakos as the standard governing constitutional disclosure claims, reasoning that “the constitutional standard of materiality must impose a higher burden on the defendant.” Agurs, 427 U. S., at 112. Agurs thus opted for its formulation of materiality, later adopted as the test for prejudice in Strickland, only after expressly noting that this standard would recognize reversible constitutional error only when the harm to the defendant was greater than the harm sufficient for reversal under Kotteakos. In sum, once there has been Bagley error as claimed in this case, it cannot subsequently be found harmless under Brecht.
The fourth and final aspect of Bagley materiality to be stressed here is its definition in terms of suppressed evidence considered collectively, not item by item. As Justice Blackmun emphasized in the portion of his opinion written for the Court, the Constitution is not violated every time the government fails or chooses not to disclose evidence that might prove helpful to the defense. 473 U. S., at 675, and n. 7. We have never held that the Constitution demands an open file policy (however such a policy might work out in practice), and the rule in Bagley (and, hence, in Brady) requires less of the prosecution than the ABA Standards for Criminal Justice, which call generally for prosecutorial disclosures of any evidence tending to exculpate or mitigate. See ABA Standards for Criminal Justice, Prosecution Function and Defense Function 3-3.11(a) (3d ed. 1993) (“A prosecutor should not intentionally fail to make timely disclosure to the defense, at the earliest feasible opportunity, of the existence of all evidence or information which tends to negate the guilt of the accused or mitigate the offense charged or which would tend to reduce the punishment of the accused”); ABA Model Rule of Professional Conduct 3.8(d) (1984) (“The prosecutor in a criminal case shall... make timely disclosure to the defense of all evidence or information known to the prosecutor that tends to negate the guilt of the accused or mitigates the offense”).
While the definition of Bagley materiality in terms of the cumulative effect of suppression must accordingly be seen as leaving the government with a degree of discretion, it must also be understood as imposing a corresponding burden. On the one side, showing that the prosecution knew of an item of favorable evidence unknown to the defense does not amount to a Brady violation, without more. But the prosecution, which alone can know what is undisclosed, must be assigned the consequent responsibility to gauge the likely net effect of all such evidence and make disclosure when the point of “reasonable probability” is reached. This in turn means that the individual prosecutor has a duty to learn of any favorable evidence known to the others acting on the government’s behalf in the case, including the police. But whether the prosecutor succeeds or fails in meeting this obligation (whether, that is, a failure to disclose is in good faith or bad faith, see Brady, 373 U. S., at 87), the prosecution’s responsibility for failing to disclose known, favorable evidence rising to a material level of importance is inescapable.
The State of Louisiana would prefer an even more lenient rule. It pleads that some of the favorable evidence in issue here was not disclosed even to the prosecutor until after trial, Brief for Respondent 25, 27, 30, 31, and it suggested below that it should not be held accountable under Bagley and Brady for evidence known only to police investigators and not to the prosecutor. To accommodate the State in this manner would, however, amount to a serious change of course from the Brady line of cases. In the State’s favor it may be said that no one doubts that police investigators sometimes fail to inform a prosecutor of all they know. But neither is there any serious doubt that “procedures and regulations can be established to carry [the prosecutor’s] burden and to insure communication of all relevant information on each case to every lawyer who deals with it.” Giglio v. United States, 405 U. S. 150, 154 (1972). Since, then, the prosecutor has the means to discharge the government’s Brady responsibility if he will, any argument for excusing a prosecutor from disclosing what he does not happen to know about boils down to a plea to substitute the police for the prosecutor, and even for the courts themselves, as the final arbiters of the government’s obligation to ensure fair trials.
Short of doing that, we were asked at oral argument to raise the threshold of materiality because the Bagley standard “makes it difficult... to know” from the “perspective [of the prosecutor at] trial... exactly what might become important later on.” Tr. of Oral Arg. 33. The State asks for “a certain amount of leeway in making a judgment call” as to the disclosure of any given piece of evidence. Ibid.
Uncertainty about the degree of further “leeway” that might satisfy the State’s request for a “certain amount” of it is the least of the reasons to deny the request. At bottom, what the State fails to recognize is that, with or without more leeway, the prosecution cannot be subject to any disclosure obligation without at some point having the responsibility to determine when it must act. Indeed, even if due process were thought to be violated by every failure to disclose an item of exculpatory or impeachment evidence (leaving harmless error as the government’s only fallback), the prosecutor would still be forced to make judgment calls about what would count as favorable evidence, owing to the very fact that the character of a piece of evidence as favorable will often turn on the context of the existing or potential evidentiary record. Since the prosecutor would have to exercise some judgment even if the State were subject to this most stringent disclosure obligation, it is hard to find merit in the State’s complaint over the responsibility for judgment under the existing system, which does not tax the prosecutor with error for any failure to disclose, absent a further showing of materiality. Unless, indeed, the adversary system of prosecution is to descend to a gladiatorial level unmitigated by any prosecutorial obligation for the sake of truth, the government simply cannot avoid responsibility for knowing when the suppression of evidence has come to portend such an effect on a trial’s outcome as to destroy confidence in its-result.
This means, naturally, that a prosecutor anxious about tacking too close to the wind will disclose a favorable piece of evidence. See Agurs, 427 U. S., at 108 (“[T]he prudent prosecutor will resolve doubtful questions in favor of disclosure”). This is as it should be. Such disclosure will serve to justify trust in the prosecutor as “the representative... of a sovereignty... whose interest... in a criminal prosecution is not that it shall win a case, but that justice shall be done.” Berger v. United States, 295 U. S. 78, 88 (1935). And it will tend to preserve the criminal trial, as distinct from the prosecutor’s private deliberations, as the chosen forum for ascertaining the truth about criminal accusations. See Rose v. Clark, 478 U. S. 570, 577-578 (1986); Estes v. Texas, 381 U. S. 532, 540 (1965); United States v. Leon, 468 U. S. 897, 900-901 (1984) (recognizing general goal of establishing “procedures under which criminal defendants are ‘acquitted or convicted on the basis of all the evidence which exposes the truth’ ” (quoting Alderman v. United States, 394 U. S. 165, 175 (1969)). The prudence of the careful prosecutor should not therefore be discouraged.
There is room to debate whether the two judges in

Question: What is the ideological direction of the decision reviewed by the Supreme Court?
A. Conservative
B. Liberal
C. Unspeciﬁable
Answer:

Answer: A