Discretionary De Novo Resentencing After Partial § 2255 Vacatur: Commentary on United States v. Abu Mezer

I. Introduction

The Second Circuit’s summary order in United States v. Abu Mezer, No. 23‑6099 (2d Cir. Nov. 25, 2025), sits at the intersection of terrorism sentencing, post‑conviction relief under 28 U.S.C. § 2255, and the evolving doctrine governing resentencing when only part of a conviction is later vacated. Although issued as a non‑precedential “summary order,” the opinion provides important guidance on how district courts should exercise their discretion when a § 924(c) firearms conviction is set aside but other, very serious counts remain intact.

The case arises from a foiled 1997 plot to detonate bombs on (or near) New York City’s subway system, for which Gazi Ibrahim Abu Mezer received concurrent life sentences on two “weapon of mass destruction” (WMD) counts, plus a consecutive 30‑year term under 18 U.S.C. § 924(c) for using a firearm in relation to a crime of violence. Decades later, developments in the law of what constitutes a “crime of violence” led to vacatur of the § 924(c) conviction under § 2255. The key dispute on appeal was whether that partial vacatur required a de novo (plenary) resentencing on the surviving counts—or at least whether the district court abused its discretion in refusing to conduct one.

The Second Circuit rejected both contentions. First, it reaffirmed (under binding circuit precedent) that § 2255 does not mandate plenary resentencing whenever a single count is vacated. Second, it held that, on these facts, the district court acted within its discretion in declining to revisit the life sentences on the WMD counts, given the unchanged seriousness of the underlying conduct and the original sentencing judge’s rationale.

While the order itself has no precedential effect under the Second Circuit’s Local Rule 32.1.1, it illustrates how the court is applying its recent precedents—particularly United States v. Peña, United States v. Orena, Kaziu v. United States, and United States v. Rigas—in the § 2255 resentencing context. For practitioners, the case underscores that defendants seeking resentencing after partial § 2255 relief must do more than invoke a change in the law; they must show a materially changed “factual mosaic” or meaningful new circumstances.

II. Summary of the Opinion

The Second Circuit (Livingston, C.J., Kearse and Lohier, JJ.) affirmed the Eastern District of New York’s amended judgment, which:

Vacated Abu Mezer’s 30‑year § 924(c) count under 28 U.S.C. § 2255; but
Left intact his life sentences on the two WMD counts, and declined to conduct a de novo resentencing on those remaining counts.

On appeal, Abu Mezer advanced two main arguments:

Mandatory De Novo Resentencing: He argued that when one of multiple counts is vacated in a § 2255 proceeding, a district court must conduct a plenary resentencing on the remaining counts, and that the Second Circuit’s decision in United States v. Peña, 58 F.4th 613 (2d Cir.), cert. denied, 144 S. Ct. 147 (2023), was wrongly decided.
Abuse of Discretion: Alternatively, he contended that even if resentencing is discretionary under § 2255, the district court abused its discretion in refusing to resentence him in light of changed legal circumstances (most notably, that the Sentencing Guidelines are now advisory rather than mandatory).

The panel held:

Peña is binding: Peña squarely holds that § 2255 gives district courts discretion to decide whether or not to conduct a de novo resentencing when one of multiple counts is vacated. A three‑judge panel cannot overrule Peña absent en banc review or Supreme Court abrogation, pursuant to In re Zarnel, 619 F.3d 156 (2d Cir. 2010).
No abuse of discretion: On the facts here, the district court did not abuse its discretion. The vacatur of the § 924(c) count stemmed from a narrow, legal change in the definition of “crime of violence,” and did not alter the “factual mosaic” underlying the WMD counts. The original sentencing judge’s detailed reasoning showed that life sentences on the WMD counts were based on the extraordinary seriousness of the conduct, not on the Guidelines or the presence of the § 924(c) count.

The panel thus concluded that a new sentencing hearing would be “an empty formality” leading to the same result, and it affirmed the district court’s decision.

III. Factual and Procedural Background

A. The 1997 Plot and Original Convictions

In July 1997, New York law enforcement disrupted a plot by Abu Mezer to bomb New York City subway trains or transit hubs. According to the Second Circuit’s description, the plan:

Involved construction of multiple bombs “designed and executed so as to wreak maximum human damage,” as evidenced by nails affixed to many devices; and
Was on the verge of execution when the New York City Police Department intervened “literally hours” before the bombs were to be placed, averting a mass‑casualty attack.

Although Abu Mezer contested his intent to bomb the subway itself, he admitted intending to place the bombs “somewhere where he could kill as many Jews as possible.” The only injuries ultimately sustained were by him and an associate, an outcome the sentencing judge expressly attributed to the police intervention.

A federal jury convicted Abu Mezer of:

One count of conspiring to use a weapon of mass destruction, in violation of 18 U.S.C. §§ 2332a(a)(2) and 2332a(c)(2);
One count of threatening to use a weapon of mass destruction, under the same WMD statute; and
One count of using a firearm in relation to a crime of violence, under 18 U.S.C. § 924(c)(1).

Judge Reena Raggi, then a district judge in the Eastern District of New York, sentenced him to:

Concurrent life terms on the two WMD counts; and
A consecutive 30‑year term on the § 924(c) count.

At the time, the Sentencing Guidelines were mandatory, but Judge Raggi calculated the Guidelines range and then independently determined that “[a] life sentence seems to be appropriate,” providing a detailed explanation focused on the severity of the conduct, the danger to the public, and the need for deterrence.

B. Post‑Conviction Proceedings and § 2255 Relief

Over the ensuing decades, Abu Mezer pursued extensive appellate and collateral relief. The specific § 2255 issue that ultimately succeeded concerned the § 924(c) count. Supreme Court decisions have narrowed the scope of what qualifies as a “crime of violence” under § 924(c). Although the order does not name the specific Supreme Court decisions, it is clear that:

The definition of “crime of violence” changed in a way that made the predicate offense(s) for his § 924(c) conviction no longer qualify; and
On that basis, the district court vacated the § 924(c) count under § 2255.

In January 2023, Judge Frederic Block (who was not the original sentencing judge) issued an order and amended judgment:

Granting § 2255 relief as to the § 924(c) conviction, thereby removing the consecutive 30‑year term; but
Denying a full de novo resentencing on the two WMD counts, concluding that he would adhere to the original life sentences based on the seriousness of the offense.

Abu Mezer appealed that amended judgment to the Second Circuit.

IV. Detailed Analysis

A. The Statutory and Doctrinal Framework

1. Section 2255 and Partial Vacatur

Under 28 U.S.C. § 2255, a federal prisoner may move to vacate, set aside, or correct a sentence imposed in violation of the Constitution or laws of the United States, or otherwise subject to collateral attack. When a prisoner is convicted on multiple counts and obtains § 2255 relief as to only one of them, a key remedial question arises:

Must the district court always conduct a full, de novo resentencing on the remaining counts, or does it have discretion to simply excise the vacated count and adjust the judgment as necessary?

In direct appeals, the Second Circuit has developed a “sentencing package” approach, recognizing that sentences for multiple counts are often interdependent. But it has also emphasized that resentencing is not always necessary if the “factual mosaic” underlying the surviving counts remains unchanged and any modification to the sentence is “strictly ministerial.”

2. De Novo (Plenary) Resentencing vs. Limited Correction

A de novo resentencing (sometimes called “plenary resentencing”) means:

The court effectively starts from scratch on the surviving counts;
New evidence, arguments, and legal developments may be considered (subject to applicable limits); and
The court recalculates the Guidelines and reweighs the statutory § 3553(a) factors as if sentencing anew.

By contrast, a limited correction involves:

Removing the vacated conviction and its sentence from the judgment;
Making any purely mechanical adjustments (e.g., total term of imprisonment); but
Leaving intact the original sentencing determinations on the surviving counts.

Section 2255 authorizes a range of remedies (“vacate and set the judgment aside and shall discharge the prisoner or resentence him or grant a new trial or correct the sentence”), which has led to circuit‑level debates on whether Congress intended resentencing to be mandatory whenever any component of a “sentencing package” is disturbed.

3. Standard of Review: Abuse of Discretion

When a district court has discretion—here, whether to conduct de novo resentencing after partial § 2255 relief—the appellate court reviews the exercise of that discretion under the “abuse of discretion” standard. In general terms, a court abuses its discretion if it:

Applies the wrong legal standard;
Bases its decision on a clearly erroneous assessment of the evidence or facts; or
Makes a decision that is outside the range of permissible choices, even if its legal framework is correct.

In Peña, the Second Circuit described a resentencing that would be “an empty formality” as an example of when a full hearing is not required. In later cases, including Orena and Kaziu, the court refined its approach to what circumstances make the denial of plenary resentencing reasonable or unreasonable, respectively.

B. Precedents Cited and Their Role

1. United States v. Peña, 58 F.4th 613 (2d Cir. 2023)

Peña is the central authority in Abu Mezer. There, the Second Circuit held that:

“§ 2255’s statutory text vests district courts with discretion … to decide whether or not to conduct a de novo resentencing” when vacating one count among multiple counts of conviction.

In other words, § 2255 does not mandate plenary resentencing whenever one of several counts is set aside. Instead, a district court may determine, case by case, whether a full resentencing is necessary or whether correction of the judgment suffices.

The Abu Mezer panel explicitly relies on Peña, noting that Abu Mezer argues it was “wrongly decided” but offering no persuasive reason—or engagement with the numerous sister‑circuit decisions cited by the government—to revisit that conclusion. The panel further emphasizes that:

“We cannot depart from Peña absent en banc consideration or abrogation of our precedent by the Supreme Court.” (citing In re Zarnel)

Peña also introduces the concept that, if resentencing would be an “empty formality” resulting in the same sentence, a district court may reasonably forgo a plenary resentencing. Abu Mezer invokes that language directly in affirming the district court’s choice.

2. In re Zarnel, 619 F.3d 156 (2d Cir. 2010)

Zarnel is cited for a familiar but critical institutional rule: a three‑judge panel of the Second Circuit cannot overrule another panel’s published decision. Only the en banc court or the Supreme Court may do so. This doctrine—sometimes called the “law of the circuit” rule—prevents horizontal panel conflicts.

In Abu Mezer, this principle disposes of the appellant’s argument that Peña was wrongly decided. Regardless of how persuasive that critique might be, the panel has no authority to overturn Peña.

3. United States v. Rigas, 583 F.3d 108 (2d Cir. 2009)

Rigas dealt with resentencing on direct appeal when some, but not all, counts were vacated. The key concept from Rigas invoked in Abu Mezer is the “factual mosaic”:

When an appellate court vacates only some of multiple counts, de novo resentencing is necessary only if the vacatur changes the “factual mosaic” related to the remaining counts. If the factual mosaic is unaltered, no further proceeding is required for those counts (beyond purely aggregate adjustments).

Abu Mezer argued that Rigas required plenary resentencing here because his sentencing package had been disturbed. The panel rejects that reading, emphasizing that Rigas specifically allows for no resentencing where the underlying facts relevant to the surviving counts are unchanged:

“Rigas expressly held that when an appellate court vacates only some of multiple counts of conviction, de novo resentencing is necessary when vacatur changes the ‘factual mosaic’ related to the remaining counts.”

In Abu Mezer, the vacatur of the § 924(c) count rests solely on a “circumscribed” change in the legal definition of “crime of violence,” not on any new or altered facts about the WMD counts. Thus, the factual mosaic of those counts remains intact. The panel concludes that Peña and Rigas are consistent: Peña sets the general rule of discretion in the § 2255 context; Rigas offers a fact‑focused test (the “factual mosaic”) for when plenary resentencing is required on direct appeal.

4. United States v. Orena, 145 F.4th 304 (2d Cir. 2025)

Orena is cited for its rejection of any “bright line rule that always requires resentencing after vacatur of a conviction whenever the resentencing would not be strictly ministerial.” The case stands for a more nuanced, discretionary approach:

Not every non‑ministerial change mandates a full resentencing; and
Courts must consider whether the vacatur meaningfully affects the rationale underpinning the surviving counts.

The panel also references Orena’s observation that the record did not show the Sentencing Guidelines were the “driving force” behind the sentence there. Abu Mezer uses similar reasoning—looking to the sentencing transcript—to conclude that the life sentences on the WMD counts were based primarily on the seriousness of the crime, not on the Guidelines.

5. Kaziu v. United States, 108 F.4th 86 (2d Cir. 2024)

Kaziu is particularly important because, unlike Abu Mezer, it holds that failure to resentence was an abuse of discretion in that case. There, as the panel notes:

The § 2255 proceeding was before a judge (Judge Block) who had not imposed the original sentence; and
The defendant presented “plausible allegations of changed circumstances” suggesting that the original rationale—that he was a “committed and unredeemed terrorist”—“no longer applie[d].”

In other words, the sentencing rationale had potentially become outdated in light of alleged post‑sentencing developments, and plenary resentencing was required to reassess the § 3553(a) factors with that new information.

In Abu Mezer, by contrast, although Judge Block was again not the original sentencing judge, the defendant did not come forward with analogous claims of changed factual circumstances. Instead, he relied on purely legal changes (the advisory nature of the Guidelines, and vacatur of § 924(c)). The panel distinguishes Kaziu on that ground: changed legal environment alone, without changed facts bearing on the sentencing rationale, did not make the refusal to resentence an abuse of discretion here.

C. The Court’s Legal Reasoning in Abu Mezer

1. Mandatory De Novo Resentencing Argument

Abu Mezer’s primary contention was that de novo resentencing is mandatory once any count is vacated under § 2255, and that Peña was wrongly decided to the extent it held otherwise.

The panel addresses this in two steps:

Reaffirmation of Peña as binding: The court notes that § 2255’s text vests discretion in district courts regarding resentencing and that this reading is consistent with other circuits. Even if one questioned Peña’s reasoning, the panel is constrained by In re Zarnel: only the en banc court or the Supreme Court may overturn that precedent.
Even under prior “de novo resentencing” jurisprudence, no mandate here: The panel points out that applying the Second Circuit’s existing resentencing cases (like Rigas) to the § 2255 context would still not compel resentencing in this case. The “factual mosaic” relevant to the WMD counts remains unaltered by the vacatur of the § 924(c) count, which was based on a narrow change in the legal definition of “crime of violence.”

Thus, the court holds that § 2255 does not require plenary resentencing, that Peña correctly interprets the statute, and that nothing in Rigas or related cases changes that conclusion.

2. Abuse of Discretion Analysis

The more nuanced question is whether the district court abused its discretion by refusing to resentence.

The panel notes that Peña did not articulate a precise standard for what constitutes an abuse of discretion in the § 2255 resentencing context. The court explicitly declines to “resolve that question today,” choosing instead to apply the general framework emerging from Peña, Orena, and Kaziu.

Several factors drive the court’s conclusion that there was no abuse of discretion here:

No change in the “factual mosaic” of the WMD counts.
The vacatur of the § 924(c) count was based solely on the “circumscribed meaning” of “crime of violence” in § 924(c). It did not cast doubt on, or materially alter, the underlying facts of the bombing plot, the defendant’s intent, the scope of the danger, or the gravity of the WMD offenses. Under Rigas, the unchanged factual mosaic weighs heavily against requiring plenary resentencing.
Lack of “plausible allegations of changed circumstances.”
Unlike in Kaziu, Abu Mezer did not present evidence or even allegations that his personal circumstances had significantly changed in ways that might undercut the original sentencing rationale (e.g., rehabilitation, renunciation of extremist beliefs, or other transformations). Thus, there was no reason to think that the predicate judgment that he was a serious and ongoing danger had been overtaken by events.
Limited relevance of the Guidelines’ advisory status.
Abu Mezer emphasized that the Sentencing Guidelines are now advisory rather than mandatory. The panel acknowledges this change but notes:
- Even as advisory, the Guidelines still recommend a life sentence; and
- The record from the original sentencing does not suggest that Judge Raggi’s decision was driven primarily (or even substantially) by the Guidelines.
Instead, she independently concluded that “a life sentence seems to be appropriate” on the WMD counts, citing the extreme gravity of the planned attack and the need for deterrence.
Original sentencing judge’s explanation is independent of § 924(c).
The panel quotes Judge Raggi’s lengthy explanation at sentencing, which:
- Separately analyzes the WMD counts, highlighting the construction of multiple shrapnel‑laden bombs and the near‑immediacy of the planned attack;
- Emphasizes that the only reason there was no mass casualty event was the NYPD’s intervention; and
- Expressly treats the 30‑year § 924(c) term as an additional congressional deterrent measure, distinct from the rationale for life on the WMD counts.
This record supports the conclusion that removal of § 924(c) does not disturb the core basis for the life sentences.
The “empty formality” rationale.
Echoing Peña, the panel accepts the district court’s conclusion that resentencing would be “an empty formality” in this case. Judge Block stated that, given the “seriousness of the offense,” he would adhere to the original life sentences. Since the primary § 3553(a) considerations (particularly the nature and circumstances of the offense and the need for deterrence and protection of the public) remain unchanged, a new hearing would almost certainly yield the same result.

In combination, these factors lead the panel to hold that the district court stayed well within the bounds of its discretion in denying plenary resentencing.

D. Harmonizing Peña, Rigas, Orena, and Kaziu

Seen together, the cited precedents form a coherent framework, which Abu Mezer implicitly applies:

Peña: § 2255 gives district courts discretion, not a mandate, to conduct de novo resentencing after partial vacatur. Resentencing can be forgone where it would be an “empty formality.”
Rigas: A de novo resentencing is required when vacatur of some counts changes the “factual mosaic” relevant to surviving counts; if the mosaic is unchanged, no resentencing is necessary.
Orena: There is no bright‑line rule requiring resentencing in every non‑ministerial case; courts should evaluate whether the vacatur meaningfully affects the sentencing rationale.
Kaziu: A failure to resentence can be an abuse of discretion where substantial, plausible allegations of changed circumstances undermine the original sentencing rationale (especially when the resentencing judge is not the original sentencing judge).

Abu Mezer fits comfortably into this structure:

It applies Peña to confirm that the district court has discretion;
It uses the “factual mosaic” concept from Rigas to determine that the underlying facts relevant to the WMD counts remain unchanged;
It heeds Orena’s admonition against a blanket rule mandating resentencing; and
It distinguishes Kaziu because Abu Mezer did not show changed personal circumstances or a shift in the sentencing rationale.

Thus, while Abu Mezer itself is a non‑precedential summary order, it exemplifies the practical application of this emerging line of cases to serious terrorism‑related convictions.

E. Complex Concepts Simplified

1. “Crime of Violence” and § 924(c)

Section 924(c) imposes mandatory consecutive sentences when a defendant uses or carries a firearm “during and in relation to” a “crime of violence” (or a drug trafficking crime). Over recent years, the Supreme Court has narrowed the statutory definition of “crime of violence,” making some predicates no longer qualify.

In Abu Mezer, the § 924(c) count was vacated not because the facts were re‑evaluated but because the meaning of “crime of violence” changed. The court notes that this is a “circumscribed” legal development that leaves the underlying factual scenario untouched.

2. “Factual Mosaic”

The “factual mosaic” metaphor, drawn from Rigas, refers to the set of facts and inferences that inform the sentencing judge’s understanding of the offense and the defendant. If vacatur or legal change disrupts that “mosaic” for the surviving counts (for example, by discrediting a major factual premise), a new sentencing may be needed. If the core facts remain the same, the need for resentencing is weaker.

3. Abuse of Discretion

“Abuse of discretion” does not mean simply that an appellate court would have decided differently. It is a deferential standard. A district court abuses its discretion only when:

It applies an incorrect legal rule;
It bases its decision on clearly wrong or unsupported facts; or
Its decision lies outside the range of reasonable choices in light of the record and law.

In this case, given the unchanged seriousness of the offense and the original judge’s clear emphasis on that seriousness rather than the Guidelines or the § 924(c) count, the Second Circuit finds the district court’s decision to omit resentencing well within the bounds of reasonable judicial choice.

4. Mandatory vs. Advisory Sentencing Guidelines

Before United States v. Booker, the Sentencing Guidelines were effectively mandatory: judges had to impose sentences within the calculated range, subject to limited departures. After Booker, the Guidelines are advisory: judges must consider them but may deviate based on the statutory factors in 18 U.S.C. § 3553(a).

Defendants often argue that advisory status could lead to lower sentences if they were resentenced today. In Abu Mezer, however, the panel notes:

The Guidelines would still recommend life; and
The original judge had already indicated that life was independently appropriate, even apart from the Guidelines.

Thus, the advisory nature of the Guidelines did not provide a compelling reason to reopen the sentence.

5. Summary Orders and Precedential Effect

The opinion expressly begins by noting that:

“Rulings by summary order do not have precedential effect.”

Under Federal Rule of Appellate Procedure 32.1 and Local Rule 32.1.1, summary orders may be cited (with appropriate notation) but are not binding precedent. They can, however, be persuasive, especially when they interpret or apply binding published decisions like Peña, Rigas, Orena, and Kaziu. Abu Mezer therefore contributes to the interpretive landscape without formally adding to the body of precedential law.

F. Impact and Future Implications

1. For Defendants Seeking Resentencing After § 2255 Relief

Abu Mezer sends a clear signal: obtaining vacatur of one count under § 2255—especially a § 924(c) count vacated purely on legal definitional grounds—does not automatically entitle a defendant to a fresh sentencing on all surviving counts. Instead:

Defendants must show that the vacated count or change in law materially altered the factual or analytical basis for the original sentence on the remaining counts; or
They must present plausible allegations of significant changed circumstances (e.g., rehabilitation, reduced dangerousness) that undermine the original sentencing rationale.

Absent such showings, courts are likely to treat resentencing as an “empty formality” and decline it, particularly where original sentences were driven by the gravity of the crime rather than the technical structure of the sentencing package.

2. For District Courts

District judges confronting partial § 2255 success should:

Recognize that they have discretion under § 2255 and Peña to decide whether a full resentencing is necessary;
Examine the original sentencing record to ascertain:
- What factors truly drove the sentence on the surviving counts; and
- Whether vacatur or post‑sentence developments have changed those factors;
Consider whether the defendant has offered credible claims of rehabilitation or other changes which might realistically influence the § 3553(a) assessment; and
Explain on the record why resentencing would—or would not—be more than an “empty formality.”

A careful, record‑based explanation, like the one endorsed in Abu Mezer, will be crucial for surviving appellate review under the abuse‑of‑discretion standard.

3. Substantive Terrorism Sentencing

On the substantive side, Abu Mezer reinforces the judiciary’s willingness to impose—and maintain—life sentences for thwarted but near‑completed terrorist plots that could have resulted in mass casualties. The case underscores that:

The absence of deaths or injuries (beyond the perpetrators) will not necessarily mitigate punishment where the intent and capability to cause mass harm are clearly established; and
The fact that law enforcement prevented an attack “hours” before execution may weigh strongly in favor of severe sentences to promote both punishment and deterrence.

Changing law on ancillary counts (such as § 924(c)) is unlikely by itself to soften such sentences unless it calls into question the reliability or completeness of the original factual record.

4. Doctrinal Trajectory

While Abu Mezer is not precedential, it suggests that the Second Circuit’s post‑Peña jurisprudence is settling into a stable position:

No categorical rule requiring resentencing for every partial § 2255 vacatur;
Focus on factual and circumstantial change—not just legal change—as the principal driver of whether resentencing is required or an abuse of discretion to deny;
Particular concern for terrorism cases (as in Kaziu and now Abu Mezer), where original sentences are often heavily grounded in assessments of dangerousness and deterrence.

Future litigation may further clarify what types of changed circumstances are sufficiently “plausible” or “material” to make denial of resentencing an abuse of discretion, especially in less extreme factual contexts.

V. Conclusion

United States v. Abu Mezer confirms, through application rather than new precedent, that district courts retain broad discretion when fashioning remedies after partial § 2255 vacatur. In the shadow of Peña, Rigas, Orena, and Kaziu, the case illustrates that:

Section 2255 vacatur of one count—especially on purely legal grounds—does not itself compel a plenary resentencing on all remaining counts;
Resentencing is not required where the “factual mosaic” underlying the surviving counts is unchanged and the original sentencing rationale remains fully intact; and
Denial of plenary resentencing will generally be upheld where a new hearing would be, in practical terms, an “empty formality” leading inexorably to the same sentence.

For practitioners, the order is a cautionary tale: obtaining partial § 2255 relief is only the first step. To secure a new sentencing hearing—and the potential for a reduced sentence—defendants must marshal evidence and arguments that genuinely alter the sentencing picture. Where, as in Abu Mezer, the underlying crime is extraordinarily grave and the original judge grounded her decision squarely in that gravity, the path to resentencing will be narrow.