Postconviction Discovery and the Materiality of Impeachment Evidence:
A Commentary on State v. Butler, 125,636 (Kan. Nov. 21, 2025)

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I. Introduction

The Kansas Supreme Court’s decision in State v. Butler, No. 125,636 (Nov. 21, 2025), is another important step in the State’s still-developing doctrine of postconviction discovery. The opinion—authored by Justice Wall—does not formally adopt the Court of Appeals decision in State v. Mundo‑Parra, 58 Kan. App. 2d 17, 462 P.3d 1211 (2020), but again assumes its framework and clarifies how demanding that standard is in practice.

At its core, the case answers a narrow but practically significant question: when a convicted defendant seeks discovery to develop a Brady/Giglio claim or a Confrontation Clause claim, is it enough to show the discovery relates to important constitutional rights, or must the defendant make a specific showing that the discovery could plausibly have affected the verdict?

In Butler, the Court holds firmly to the latter position. The defendant, Marcus G. Butler, sought postconviction discovery about alleged perjury by a crime-scene investigator (CSI), Officer Jackie Green, who had testified at his murder trial. He argued that the State had suppressed impeachment evidence about Green, violating his rights under Brady v. Maryland, 373 U.S. 83 (1963), and Giglio v. United States, 405 U.S. 150 (1972), and his Sixth Amendment right to confront and impeach a witness. The Court, however, concludes that because Officer Green’s testimony was not material to the conviction, Butler failed to show that the requested discovery was needed to protect “substantial rights” within the meaning of Mundo‑Parra.

In addition, the Court reinforces an important procedural principle: a motion to alter or amend judgment under K.S.A. 60‑259 is not a vehicle for raising new arguments that could have been presented in the original motion. That civil doctrine is expressly applied here in the criminal postconviction-discovery context.

This commentary examines the opinion in depth, situating it within Kansas precedent, explaining its reasoning, and assessing its implications for future postconviction discovery and constitutional claims in Kansas criminal cases.

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II. Summary of the Opinion

A. Background and Procedural Posture

• Butler was convicted by a jury of first-degree felony murder, attempted aggravated robbery, and conspiracy to commit aggravated robbery arising from a 2014 home invasion. The State’s case relied largely on testimony from three coworkers who implicated Butler as the would-be robber and shooter.
• Crime-scene investigator Officer Jackie Green testified about firearms and shell casings found at the scene (.357 revolver, .40 caliber semiautomatic pistol, .32 caliber shell casings), but no physical evidence tied Butler to the crime.
• On direct appeal, the Kansas Supreme Court affirmed his convictions (State v. Butler, 307 Kan. 831, 416 P.3d 116 (2018)).
• Butler then filed a first postconviction-discovery motion under Mundo‑Parra, seeking coworkers’ cellphone data and original statements of apartment residents. The district court denied the motion; the Supreme Court affirmed in State v. Butler, 315 Kan. 18, 503 P.3d 239 (2022), for failure to show how the discovery was needed to protect “substantial rights.”
• While that first appeal was pending, Butler filed a second postconviction-discovery motion, this time alleging Officer Green had committed perjury in federal court and that the State had failed to disclose this impeachment material before trial. He sought all documents and communications related to Green’s alleged perjury.
• The district court denied the second motion, finding Butler had not shown how the requested discovery could have affected the outcome of his trial. It also denied Butler’s subsequent K.S.A. 60‑259 motion to alter or amend judgment, viewing it as an improper attempt to raise new arguments after the fact.
• Butler appealed directly to the Kansas Supreme Court, which considered the case on its summary calendar, without oral argument.

B. Holdings

The Kansas Supreme Court affirmed, holding that:

1. No abuse of discretion in denying postconviction discovery: Assuming without deciding that Mundo‑Parra sets out the correct standard, Butler failed to satisfy its second prong. He did not show that the requested discovery related to a factual matter that could affect an essential right in a way that might change the outcome of the trial.
2. Impeachment of a non-material witness does not justify postconviction discovery: Officer Green’s testimony was not material to Butler’s conviction because the State’s case rested on coworker testimony, not physical evidence. Impeaching Green would not undermine the core evidence of guilt.
3. Motion to alter or amend is not a second bite at the apple: The district court reasonably denied Butler’s K.S.A. 60‑259 motion because he attempted to raise additional arguments and theory (that Green was a key defense witness) that he could have raised in his original motion.
4. Any factual misstatement about prior access to discovery was harmless: Even if the district court erred in suggesting Butler already possessed the requested materials (via an open-records request), that factual issue did not underlie the dispositive legal conclusion and therefore did not constitute an abuse of discretion.

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III. Legal Framework

A. Abuse-of-Discretion Standard

The Court frames its review under a familiar standard:

“A district court abuses its discretion if no reasonable person could agree with its decision or if its exercise of discretion is founded on a legal or factual error.” (State v. Richardson, 316 Kan. 752, 753, 521 P.3d 1111 (2022).)

This standard applies both to:

• the denial of postconviction discovery (Richardson), and
• the denial of a motion to alter or amend judgment (State v. Campbell, 317 Kan. 511, 529, 532 P.3d 425 (2023)).

The opinion reiterates that the burden of proving an abuse of discretion rests on the party alleging it—here, the defendant. The Court cites its own earlier decision in Butler, 315 Kan. at 21, for this allocation of burden.

B. Postconviction Discovery under Mundo‑Parra and Butler (2022)

In Mundo‑Parra, the Court of Appeals recognized a limited right to postconviction discovery where the requested materials are needed to protect a defendant’s “substantial rights.” The Kansas Supreme Court has not yet expressly adopted that standard as binding statewide, but in multiple cases—Richardson, Butler (2022), and now Butler (2025)—it has assumed the standard is correct and applied it.

Under Mundo‑Parra, a defendant must:

1. Identify specific subject matter for discovery; and
2. Explain why that discovery is necessary to protect substantial rights.

The Supreme Court in Butler (2022) elaborated that a “substantial right” is:

“a factual matter that could affect an essential right that potentially affects the outcome of the proceedings.” (315 Kan. at 23.)

The 2025 opinion again uses this formulation, tying “substantial rights” squarely to potential outcome-changing significance, not merely to the general importance of the underlying constitutional right.

C. Brady, Giglio, and the Confrontation Clause

1. Brady and Giglio

Under Brady v. Maryland, prosecutors must disclose evidence favorable to the accused that is “material either to guilt or to punishment.” This duty:

• is affirmative and does not depend on defense requests, and
• applies regardless of the prosecutor’s good or bad faith.

The Kansas Supreme Court quotes itself in State v. Breitenbach, 313 Kan. 73, 97, 483 P.3d 448 (2021), to restate the principle:

“Prosecutors have a positive duty to disclose evidence favorable to the accused when the evidence is material either to guilt or to punishment, irrespective of the good faith or bad faith of the prosecution.”

Giglio v. United States, 405 U.S. 150, extends Brady to impeachment evidence—information that undermines the credibility of a key prosecution witness.

2. Confrontation Clause / Right to Impeach

Separate from Brady, the Sixth Amendment’s Confrontation Clause guarantees the right to cross-examine and impeach adverse witnesses. The Court cites:

State v. Brooks, 297 Kan. 945, 952, 305 P.3d 634 (2013) (the right to impeach a complaining witness is a fundamental Sixth Amendment right).

In Butler, the defendant invokes both:

• his Brady/Giglio due process right to favorable, material evidence, and
• his Sixth Amendment right to impeach a witness.

The Court accepts that these are “important rights,” but insists that in the postconviction discovery setting, the defendant must go further and show how the discovery could realistically have altered the outcome of trial.

D. Motions to Alter or Amend under K.S.A. 60‑259

Butler filed a K.S.A. 60‑259 motion to alter or amend judgment after his second discovery motion was denied, trying to bolster his arguments. The Supreme Court affirms the district court’s refusal to consider new arguments in that motion, citing:

• Ross‑Williams v. Bennett, 55 Kan. App. 2d 524, 564, 419 P.3d 608 (2018) – it is proper to deny a motion to alter or amend if the movant could have raised the argument or evidence before the final order with reasonable diligence.
• Sierra Club v. Mosier, 305 Kan. 1090, 1122, 391 P.3d 667 (2017) – as a general rule, parties may not raise new arguments in a motion for reconsideration.

Butler thus confirms these civil principles apply in criminal postconviction-discovery proceedings as well.

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IV. Detailed Analysis of the Court’s Reasoning

A. Application of the Mundo‑Parra Test

The Court begins by assuming, but not deciding, that Mundo‑Parra is the correct standard. It then zeroes in on the second prong: whether Butler showed that the requested discovery is necessary to protect “substantial rights.”

Butler grounded his request in two asserted substantial rights:

1. His due process right to Brady/Giglio material (favorable and material evidence, including impeachment of a State witness).
2. His right under the Confrontation Clause to impeach a complaining witness.

The Court accepts that these rights are fundamental, but emphasizes that merely tying the discovery to a constitutional right is insufficient. The defendant must also show a plausible nexus between the discovery and a different verdict:

“But that is not enough to satisfy the test in Mundo‑Parra. … Butler must also explain how the requested discovery could have affected the outcome of his trial.” (slip op. at 6.)

This is the central doctrinal clarification of the case: the “substantial rights” test is outcome-focused, not merely rights-focused. It is not enough that the discovery might reveal a constitutional violation in the abstract; it must have potential to matter to guilt or punishment.

B. Was Officer Green’s Testimony Material to the Conviction?

1. Butler’s Theory: Green as a “Material” Witness

In his second discovery motion, Butler argued that:

• Officer Green was a “material witness” because she collected physical evidence (guns, shell casings) and laid foundation for related photographs.
• If he had impeachment evidence of her alleged perjury in another proceeding, he could attack her credibility and challenge the foundation and chain of custody for the physical evidence.
• Such attacks could, in his view, undermine confidence in the overall case and thus his conviction.

2. The Court’s Response: Green’s Testimony Was Not Material

The Court decisively rejects Butler’s premise:

“But Butler’s premise is flawed—Officer Green’s testimony was not material to his conviction.” (slip op. at 7.)

The Court emphasizes:

• Officer Green’s role was limited to describing what firearms and casings were recovered at the scene and laying the foundation for photographs and physical evidence.
• Her testimony provided context for the investigation but did not link Butler to any physical evidence. In fact, “no physical evidence tied Butler to the crime.”
• The State’s case “relied on witness testimony directly implicating Butler”—i.e., the coworkers’ accounts.

Against that backdrop, impeachment of Green would not undermine the heart of the State’s case:

“The requested discovery may have helped Butler to attack Officer Green’s credibility and challenge the foundation or chain of custody for the physical evidence. But it would have had no bearing on the incriminating witness testimony that convicted him.” (slip op. at 7.)

Thus, even assuming:

• Officer Green had committed perjury in federal court, and
• the State had suppressed that information in violation of Brady/Giglio,

the Court finds that none of this could reasonably have altered the verdict, given that the coworkers’ testimony—not the physical evidence—drove the conviction.

By drawing this sharp line, the Court effectively holds: impeachment of a largely background or non-key witness will generally not satisfy the “substantial rights” requirement for postconviction discovery, absent a clear link to the verdict.

C. The Motion to Alter or Amend Judgment

1. Procedural Reason: Not a Second Bite at the Apple

After the district court denied the second discovery motion, Butler filed a motion to alter or amend judgment under K.S.A. 60‑259. In it, he:

• did not so much correct errors as expand his theory of why Officer Green was important, and
• presented more detailed arguments about how her testimony allegedly assisted the defense and why impeaching her was still necessary.

The district court refused to consider those expanded arguments, reasoning that they could have been raised in the original motion and that a 60‑259 motion is not a vehicle to relitigate or supplement arguments that could have been presented earlier.

The Supreme Court agrees:

“[I]t is proper for a district court to deny a motion to alter or amend if the movant could have—with reasonable diligence—presented the argument or evidence before the entry of the final order.” (citing Ross‑Williams, 55 Kan. App. 2d at 564.)

And:

“As a general rule, a party may not raise a new argument in a motion for reconsideration.” (citing Sierra Club, 305 Kan. at 1122.)

Because Butler did not claim that the district court’s factual finding (that he could have made these arguments earlier) was erroneous, and because the court’s application of this legal rule was correct, there was no abuse of discretion.

2. Substantive Point: Even on the Merits, Butler’s New Theory Fails

The Supreme Court goes further and explains that even if the district court had considered Butler’s expanded arguments on the merits, they still would not meet the Mundo‑Parra standard.

In his 60‑259 motion, Butler changed tack and argued that Officer Green was actually a key witness for the defense, not the State. The Court carefully reconstructs her testimony:

• Green testified that the .40‑caliber semiautomatic pistol found at the scene had 12 bullets in a 20‑round magazine.
• She also testified that:
  • the .40‑caliber semiautomatic could fire .32‑caliber bullets; and
  • .32‑caliber and .40‑caliber bullets could be mixed in the same magazine.

This testimony was potentially exculpatory when combined with other evidence:

• The victim was shot seven times.
• The magazine had capacity for eight more bullets.
There were several .32‑caliber shell casings at the scene.
• There was some evidence that a male visitor to the apartment may have owned the .40‑caliber pistol.

Defense counsel could thus argue that the visitor, not Butler, might have been the shooter, using Green’s testimony to suggest that the .40‑caliber gun (in the visitor’s possession) could have fired the .32‑caliber rounds that killed the victim.

Crucially, however, the Court observes that the State re‑called another CSI officer to rebut this potentially exculpatory testimony. That officer testified that:

• a .40‑caliber firearm could not fire multiple .32‑caliber rounds; and
• .40‑caliber and .32‑caliber ammunition could not be mixed in the same magazine.

This rebuttal evidence largely negated the exculpatory inference from Green’s statements.

With that evidentiary landscape in mind, the Court poses a practical question:

“But if Officer Green’s trial testimony was exculpatory, why would Butler now request discovery to impeach her?” (slip op. at 9.)

Impeaching Green would only:

• undercut her potentially favorable testimony suggesting someone else might be the shooter, and
• indirectly reinforce the credibility of the rebuttal CSI witness who contradicted her.

Thus, the Court concludes:

“[T]he discovery could not have affected the outcome of the trial—it would have reinforced the jury’s verdict. … And Butler’s requested discovery would only bolster the incriminating testimony of the other CSI officer.” (slip op. at 9.)

In other words, even under Butler’s revised theory, the discovery does not help him; it would harm his position by undermining exculpatory evidence and strengthening the State’s rebuttal.

D. Alleged Factual Error and Harmlessness

Finally, Butler argued that the district court abused its discretion by making a factual error—specifically, finding that he already had the requested discovery because he had filed an open-records request and described the materials in detail in his motion.

In his 60‑259 motion, Butler asserted that he did not actually receive the materials through his open-records request. The Supreme Court declines to resolve the factual conflict, explaining that:

• Even if the district court was wrong about Butler already having the materials, that finding was not central to the court’s legal conclusion.
• The dispositive conclusion—that Butler failed to satisfy the second prong of Mundo‑Parra—did not depend on whether he already possessed the documents.

The Court cites State v. Bilbrey, 317 Kan. 57, 63, 523 P.3d 1078 (2023), for the proposition that a factual error only amounts to an abuse of discretion if it pertains to a factual finding on which the legal conclusion or exercise of discretion is based. Here, the questionable factual finding was collateral.

Because the legal conclusion is fully supported by the materiality analysis described above, any factual misstatement about Butler’s prior access to the documents is harmless and does not taint the ruling.

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V. Precedents Cited and Their Influence

A. Mundo‑Parra and Its Shadow Adoption

State v. Mundo‑Parra, 58 Kan. App. 2d 17 (2020), is the foundational case for postconviction discovery in Kansas. It articulates the two‑part test:

1. Identify the specific subject matter sought.
2. Explain why discovery is necessary to protect substantial rights.

The Supreme Court in Butler (2022) and again in Butler (2025) has:

• not formally adopted Mundo‑Parra as binding statewide doctrine, but
• consistently assumed without deciding that it states the correct standard.

Substantively, however, the Court is now consistently applying that standard and adding gloss—especially on what “substantial rights” requires. Practitioners can safely treat Mundo‑Parra as functionally operative, albeit without formal Supreme Court adoption.

B. Kansas Cases on Abuse of Discretion

• State v. Richardson, 316 Kan. 752, 521 P.3d 1111 (2022) – supplies the definition of abuse of discretion: no reasonable person would agree with the decision, or it rests on legal/factual error. Butler cites this to frame the standard of review for postconviction discovery.
• State v. Campbell, 317 Kan. 511, 532 P.3d 425 (2023) – confirms the same abuse-of-discretion standard applies to motions to alter or amend under K.S.A. 60‑259.
• State v. Bilbrey, 317 Kan. 57, 523 P.3d 1078 (2023) – clarifies that a factual error amounts to abuse of discretion only if the erroneous finding underlies the legal conclusion or discretionary decision. Butler relies on this to dismiss concerns about collateral factual misstatements.

C. Prior Butler Decisions

• State v. Butler, 307 Kan. 831, 416 P.3d 116 (2018) – the direct appeal opinion affirming Butler’s convictions. It provides the detailed factual record for the underlying crime and trial.
• State v. Butler, 315 Kan. 18, 503 P.3d 239 (2022) – the first postconviction-discovery appeal, where the Court held Butler had failed to explain how requested discovery (coworkers’ phone data and residents’ statements) was needed to protect substantial rights. The 2025 opinion repeatedly cites this case for (1) the meaning of “substantial right,” and (2) the proposition that the defendant bears the burden of proving abuse of discretion.

Together, these decisions create a running line of authority: Butler is not only about one defendant’s case, but also the principal Kansas vehicle for refining the law of postconviction discovery.

D. Brady, Giglio, and Kansas Applications

• Brady v. Maryland, 373 U.S. 83 (1963) – establishes the State’s duty to disclose favorable, material evidence to the defense.
• Giglio v. United States, 405 U.S. 150 (1972) – extends Brady to impeachment evidence about government witnesses.
• State v. Breitenbach, 313 Kan. 73, 483 P.3d 448 (2021) – is cited for a succinct restatement of the Brady duty in Kansas law.

While Butler does not directly decide a Brady/Giglio violation on the merits (because it is at the pre‑discovery stage), it uses the Brady emphasis on materiality (outcome significance) to shape what qualifies as a “substantial right” under the Mundo‑Parra test.

E. Confrontation Clause: State v. Brooks

State v. Brooks, 297 Kan. 945, 305 P.3d 634 (2013), recognizes that the right to impeach a complaining witness is integral to the Sixth Amendment right to confrontation. In Butler, the defendant invokes this right to frame his discovery request as constitutionally grounded.

The Court acknowledges the right is “fundamental,” but uses Brooks only to establish the nature of the right, not to alter the outcome-focused lens of Mundo‑Parra. The case thus underscores that a fundamental right, by itself, does not compel postconviction discovery absent a showing of potential impact on the verdict.

F. Motions to Alter or Amend: Ross‑Williams and Sierra Club

• Ross‑Williams v. Bennett, 55 Kan. App. 2d 524, 419 P.3d 608 (2018) – stands for the principle that a motion to alter or amend judgment should not be used to raise arguments or present evidence that the movant could have offered before the final judgment with reasonable diligence.
• Sierra Club v. Mosier, 305 Kan. 1090, 391 P.3d 667 (2017) – articulates the general rule that new arguments cannot be raised in a motion for reconsideration.

By invoking these civil precedents in the criminal postconviction context, the Court signals that postconviction discovery motions are subject to the same finality-oriented procedural discipline as civil motions.

G. Impeaching One’s Own Witness: State v. Blocker

The Court also cites State v. Blocker, 211 Kan. 185, 505 P.2d 1099 (1973), which holds that a party may introduce competent evidence to prove a fact even if that evidence tends to impeach or contradict the party’s previous witness.

This is used to explain why the State could properly recall another CSI officer to rebut and effectively impeach Officer Green’s potentially exculpatory testimony. The citation reinforces the idea that internal inconsistency among a party’s witnesses does not preclude the party from offering clarifying or corrective testimony.

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VI. Complex Concepts Simplified

A. “Abuse of Discretion”

A decision is an “abuse of discretion” when:

• no reasonable judge could have made that decision, or
• the judge applied the wrong legal rule or relied on clearly wrong facts.

This is a deferential standard. The appellate court does not ask what it would have done; it asks whether the district court’s choice was reasonable and legally/factually sound.

B. “Substantial Right” in the Mundo‑Parra Context

A “substantial right” is:

• more than just a technical or minor interest; it is “essential” and “capable of legal enforcement,” and
• critically, under Butler, it is one that could affect the outcome of the proceedings.

So, for postconviction discovery, it is not enough that the evidence relates to a constitutional right. The defendant must show that the evidence could realistically change the verdict or sentence.

C. “Materiality” under Brady and in Butler

Evidence is “material” under Brady if there is a reasonable probability that, had it been disclosed, the result of the proceeding would have been different.

In Butler:

• The Court imports this idea into the “substantial rights” inquiry: if evidence is not material in the Brady sense (i.e., it couldn’t change the outcome), it will likewise fail the Mundo‑Parra test.
• Officer Green’s testimony is deemed non-material because it played no meaningful role in connecting Butler to the crime.

D. Impeachment Evidence vs. Exculpatory Evidence

• Exculpatory evidence directly tends to show the defendant did not commit the crime or is less culpable.
• Impeachment evidence undercuts the credibility of a witness (showing bias, prior inconsistent statements, perjury in other proceedings, etc.).

Both types can be “favorable” under Brady/Giglio. However, if impeachment pertains only to a marginal or non-key witness, it may not rise to the level of “materiality.” Butler illustrates this: even if Green’s credibility could be attacked, that would not matter much if the conviction rested on entirely separate evidence.

E. Chain of Custody

“Chain of custody” refers to the documented sequence of custody, control, transfer, and analysis of physical evidence. Challenges to chain of custody seek to cast doubt on whether an item introduced at trial is the same one collected at the scene and has not been tampered with or contaminated.

In Butler, the defendant suggested he could use impeachment evidence against Green to question chain of custody for firearms and shell casings, but the Court found this immaterial because no physical evidence ever linked Butler directly to the crime.

F. Motions to Alter or Amend Judgment (K.S.A. 60‑259)

A motion to alter or amend judgment is designed for:

• correcting clear legal or factual errors,
• addressing overlooked issues, or
• adjusting relief in light of newly discovered evidence that could not reasonably have been presented earlier.

It is not intended to:

• rehash old arguments, or
• raise new arguments that could have been made before judgment.

Butler applies this principle strictly in the postconviction criminal context.

G. “Off-Grid” Felony and Direct Supreme Court Jurisdiction

Kansas categorizes most felonies on a sentencing grid, but certain serious crimes—such as first-degree murder—are designated “off‑grid.” These offenses:

• carry life sentences rather than grid-based terms, and
• qualify for direct appeal to the Kansas Supreme Court under K.S.A. 22‑3601(b)(3) and (4).

Butler’s first-degree felony murder conviction, an off-grid person felony under K.S.A. 21‑5402(b), provides the jurisdictional hook for the Supreme Court’s direct review.

H. Summary Calendar

The case was decided on the Supreme Court’s “summary calendar,” under Supreme Court Rule 7.01(c)(4). This means:

• the Court deemed the case appropriate for decision without oral argument, and
• it decided the case based on the parties’ briefs alone.

This procedural note underscores that the Court viewed the legal issues as sufficiently clear and controlled by existing doctrine to forgo further oral presentation.

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VII. Practical and Doctrinal Impact

A. Tightening the Standard for Postconviction Discovery

Butler confirms that the Mundo‑Parra framework is stringent. To obtain postconviction discovery, a defendant must:

1. Identify with precision what is sought; and
2. Persuasively explain how that discovery could yield evidence that would likely affect the verdict or sentence.

Merely invoking serious constitutional rights—Brady, Giglio, Confrontation Clause—is insufficient unless the requested materials are plausibly outcome-changing. Impeachment evidence about a secondary or background witness will rarely qualify.

B. Clarifying the Role of “Key” vs. “Non-Key” Witnesses

The case draws a functional distinction between:

• Key witnesses, whose testimony is central to the State’s theory of guilt (e.g., cooperating accomplices, victims, primary eyewitnesses); and
• Non-key or background witnesses, whose testimony provides context or explains the investigation but does not meaningfully connect the defendant to the crime.

Butler suggests that impeachment discovery aimed at non-key witnesses will often fail the substantial-rights test, particularly where the conviction rests on independent, direct evidence of guilt.

C. Interaction with Brady/Giglio Materiality

Although Butler is not directly a Brady adjudication, it effectively aligns:

• the Mundo‑Parra “substantial rights” requirement with
• the Brady/Giglio “materiality to guilt or punishment” requirement.

Practitioners should assume that if impeachment or exculpatory evidence would not be considered material under Brady, it will likewise not justify postconviction discovery under Mundo‑Parra.

D. Strategic Lessons for Defense Counsel

• Build a concrete theory of outcome impact. When seeking postconviction discovery, defense counsel must be able to explain—ideally with record citations and logical chains—how the new material could undermine the key pillars of the prosecution’s case.
• Focus on primary evidence of guilt. Discovery targeting tangential witnesses or peripheral issues is unlikely to meet the standard. Efforts should be concentrated on evidence that bears directly on eyewitnesses, accomplice testimony, confessions, or central forensic links.
• Avoid speculative or internally inconsistent theories. Butler’s late-stage claim that Green was a key defense witness, while seeking to impeach her, illustrates the perils of inconsistent theories that, if accepted, would actually strengthen the State’s case.
• Use initial motions comprehensively. Because K.S.A. 60‑259 motions cannot be used to bring new arguments that could have been presented earlier, defense counsel must treat the initial postconviction‑discovery motion as their primary and most complete submission.

E. Guidance for Prosecutors and Courts

• Emphasize materiality and record-based analysis. Prosecutors and courts can rely on Butler to argue that discovery should be denied when the requested information relates only to peripheral aspects of the case.
• Document and disclose key impeachment material timely. While Butler narrows postconviction access to discovery, prosecutors are still bound by robust pretrial Brady/Giglio duties. Failure to disclose truly material impeachment evidence for key witnesses remains reversible error.
• Maintain orderly postconviction procedure. The reaffirmed rule against raising new arguments in motions to alter or amend supports procedural finality and efficient resolution of postconviction motions.

F. Doctrinal Trajectory: Mundo‑Parra by Practice if Not by Name

Although the Supreme Court continues to say it has “yet to adopt Mundo‑Parra as the controlling standard,” it has now:

• applied its test repeatedly across multiple cases, and
• developed a body of case law using its language and concepts.

Butler therefore reinforces the practical reality that Mundo‑Parra governs postconviction discovery in Kansas, even in the absence of a formal adoption statement. Future decisions may either eventually adopt it explicitly or continue this pattern of applied assumption.

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VIII. Conclusion

State v. Butler (2025) does not revolutionize Kansas law, but it solidifies and sharpens two significant doctrines:

1. Postconviction discovery is tightly constrained. Under the Mundo‑Parra framework as applied in Butler, a defendant seeking discovery must show not just a connection to an important constitutional right, but a credible prospect that the requested information could have altered the verdict or sentence. Impeachment of a non-key witness such as a background CSI officer generally will not meet this threshold.
2. Motions to alter or amend are not vehicles for new theories. By importing civil precedent into the criminal postconviction context, the Court insists that parties raise all arguments with reasonable diligence in their initial motions. Post‑judgment motions cannot be used to salvage or remake a deficient presentation.

The opinion’s granular analysis of Officer Green’s testimony—both as a purportedly material State witness and later as a supposedly key defense witness—illustrates the Court’s focus on practical materiality: what actually mattered to the jury’s decision. In that sense, Butler is less about abstract doctrine and more about aligning postconviction discovery with common-sense judgments about what evidence might realistically have changed the outcome.

For Kansas practitioners, Butler is a clear signal: postconviction discovery is available only in narrow circumstances, and success depends on building a disciplined, outcome‑oriented argument anchored firmly in the trial record and the central evidence of guilt.