United States v. Parlin: Sufficiency Review Uses All Admitted Evidence; Harmless-Error Affirmance Without Deciding Lay vs. Expert Drug-Quantity Testimony

Introduction

In United States v. Parlin (1st Cir. Mar. 11, 2026), the First Circuit affirmed Jacob Parlin’s jury convictions for (1) conspiracy to distribute and to possess with intent to distribute methamphetamine, in violation of 21 U.S.C. § 846, and (2) distribution of and possession with intent to distribute methamphetamine, in violation of 21 U.S.C. § 841(a)(1), (b)(1)(A)(viii).

The government’s case was built around DEA wiretaps capturing conversations among Parlin, Harry Tam, and Vincent Duong that, in the government’s view, revealed a methamphetamine distribution operation. After New Hampshire police stopped Parlin, officers found two heat-sealed bags of 100% pure methamphetamine totaling 882.8 grams (nearly two pounds), along with paraphernalia consistent with drug use.

The central trial dispute was intent: Parlin claimed he was a user, not a distributor. On appeal, he pressed two linked arguments: (i) the district court improperly permitted Lieutenant Lindsey Cunningham to testify as a lay witness that the quantity found was inconsistent with personal use, and (ii) without that testimony, the evidence was insufficient to prove intent to distribute (an element of both counts as charged and tried).

Summary of the Opinion

The First Circuit affirmed on both counts for two independent reasons:

1. Sufficiency review considers all evidence actually admitted at trial, whether or not it was admitted correctly; therefore, Parlin’s “sufficiency-without-the-challenged-testimony” argument failed as a matter of law.
2. Even if Lieutenant Cunningham’s testimony were assumed erroneous, any error was harmless because the recorded calls and surrounding evidence made it “highly improbable” that the jury’s verdict turned on the challenged testimony—described memorably as “more frosting than cake.”

Analysis

Precedents Cited

1) United States v. Santiago-González

The court treated United States v. Santiago-González, 825 F.3d 41 (1st Cir. 2016), as controlling on the proper scope of sufficiency review: appellate courts assess whether the verdict is supported by all evidence the jury heard, “without regard to whether the trial court’s evidentiary rulings were correct.” That rule foreclosed Parlin’s attempt to re-run sufficiency as a counterfactual exercise (i.e., assuming the exclusion of Cunningham’s testimony).

2) United States v. Ramirez-Rivera and Lockhart v. Nelson

The opinion reinforced the rationale behind the Santiago-González rule by quoting United States v. Ramirez-Rivera, 800 F.3d 1 (1st Cir. 2015), which in turn quotes Lockhart v. Nelson, 488 U.S. 33 (1988): reversals for evidentiary insufficiency have double-jeopardy consequences (they bar retrial), while reversals for evidentiary error generally do not. By insisting that sufficiency be measured on the trial record as it stands, the court preserves this doctrinal separation: the “failed proof” remedy (acquittal) is reserved for true insufficiency, while “failed process” (erroneous admission/exclusion) ordinarily yields a new trial.

3) United States v. Piper

Citing United States v. Piper, 298 F.3d 47 (1st Cir. 2002), the court emphasized the remedial distinction: if evidence was improperly admitted and prejudiced the defendant, the typical remedy is a new trial—not an appellate acquittal disguised as a sufficiency ruling. This framed Parlin’s proper avenue of relief as an evidentiary-error/harmlessness inquiry rather than a sufficiency challenge conditioned on excluding evidence.

4) United States v. Sanabria and United States v. Meises

For harmless error, the court invoked United States v. Sanabria, 645 F.3d 505 (1st Cir. 2011) (quoting United States v. Meises, 645 F.3d 5 (1st Cir. 2011)): the government must show it is “highly probable” the error did not influence the verdict. This standard supplied the tool the panel used to affirm without deciding whether Cunningham’s lay/expert classification was correct.

Legal Reasoning

1. Step one: rejecting the “conditional sufficiency” theory. Parlin argued the evidence would be insufficient “without” the officer’s testimony. The court treated that as a non-starter under United States v. Santiago-González: sufficiency is assessed based on the evidence admitted, period.
2. Step two: assuming (without deciding) error and finding harmlessness. Rather than resolve whether Cunningham’s testimony was impermissible undisclosed expert testimony or permissible lay testimony grounded in personal observations, the panel held that any error would not warrant reversal because the government met the “highly probable” harmlessness burden. The recorded calls, in the panel’s view, “made it crystal clear” that Parlin was engaged in selling methamphetamine—discussing pricing, competition, “customers,” supply quality (“no cut stuff”), and profits during the COVID-19 period.
3. Central evidentiary theme: intent inferred from business-like communications, not just quantity. While the district court instructed the jury that intent to distribute may be inferred from a quantity larger than personal use, the court of appeals stressed that the wiretap evidence supplied direct context of distribution activity. Thus, even though the prosecutor highlighted Cunningham’s “grams per day” framing, the calls and the circumstances of transport (including the value and packaging) made the personal-use narrative implausible.

Impact

• Clarifies appellate framing for defendants: when challenging an officer’s “user vs. distributor quantity” testimony, defendants should not expect to win by re-labeling the issue as “insufficiency absent that testimony.” The sufficiency inquiry will include the disputed evidence if the jury heard it.
• Encourages harmless-error resolutions where other evidence is strong: the panel’s “frosting than cake” approach signals that appellate courts may affirm without deciding difficult Rule 701/702 boundaries when independent evidence (here, wiretaps) overwhelmingly establishes intent to distribute.
• Highlights the evidentiary power of wiretaps in drug cases: conversations about pricing, market competition, “customers,” product purity/cutting, and reinvestment can function as near-direct proof of distribution intent, diminishing the marginal importance of quantity-opinion testimony.
• Institutional reinforcement of remedy separation: by emphasizing Lockhart v. Nelson’s logic, the opinion reinforces the doctrinal boundary between acquittal for insufficient evidence and retrial for evidentiary error—an important constraint on how appellate courts structure reversals.

Complex Concepts Simplified

Sufficiency of the evidence

A claim that, even taking the trial evidence in the light most favorable to the verdict, no rational jury could find guilt beyond a reasonable doubt. On appeal, this review uses the evidence the jury actually heard, even if some of it may have been admitted in error.

Evidentiary error vs. insufficiency (why it matters)

If evidence is legally insufficient, the defendant is entitled to an acquittal and retrial is barred. If evidence was admitted improperly, the usual remedy is a new trial, because the problem is the procedure, not necessarily the government’s ability to prove guilt.

Harmless error (“highly probable”)

Even if the trial court made a mistake admitting evidence, the conviction stands if it is highly probable the mistake did not affect the verdict. The court found the wiretap conversations and circumstances of possession made the outcome essentially inevitable.

Lay vs. expert testimony (the dispute in this case)

“Lay” testimony generally comes from personal perception and experience; “expert” testimony relies on specialized knowledge and triggers pretrial disclosure requirements. Here, the district court limited the officer to what he had personally seen in meth cases, but the court of appeals did not decide the classification because it found harmlessness.

Intent to distribute inferred from quantity

Jurors may infer intent to distribute when the quantity possessed exceeds what is typically needed for personal use. The instruction permitted (but did not require) that inference; the appellate court emphasized that the recorded calls independently supported intent to distribute.

Conspiracy (21 U.S.C. § 846)

An agreement to commit a drug-trafficking offense, plus the defendant’s knowing and voluntary participation. The wiretaps were central to showing coordination and shared objectives.

Conclusion

United States v. Parlin reinforces two practical rules for federal criminal appeals in the First Circuit: (1) sufficiency review evaluates the evidence as admitted at trial, not a hypothetical record with disputed evidence removed; and (2) when the remaining evidence is overwhelming—here, wiretap conversations indicating a drug-distribution business—any possible error in admitting a law-enforcement officer’s quantity-related opinion testimony may be deemed harmless, allowing affirmance without resolving the lay-versus-expert boundary.