Defining Waiver of Daubert Challenges and Batson Affiliation Strikes
United States v. Corey Hamlet

Introduction

United States v. Corey Hamlet (3d Cir. 2025) is a consolidated appeal from convictions under federal racketeering, firearms, murder and related statutes. Appellants Corey Hamlet, Ahmad Manley and Tony Phillips—all members or associates of the Newark Crips—challenged the admission of expert Cell Site Location Information (“CSLI”) testimony, the prosecution’s exercise of peremptory strikes under Batson v. Kentucky, certain evidentiary rulings, and alleged prosecutorial misstatements during closing argument. The Third Circuit, in an opinion by Judge Porter, addressed: (1) whether a Daubert objection to CSLI evidence preserved appellate review after counsels’ “no objection” waiver at retrial; (2) whether striking a juror for affiliation with the NAACP is per se racially discriminatory; (3) claims of evidentiary error including Jencks Act disclosures and character evidence; and (4) allegations of prosecutorial misstatement regarding CSLI precision.

Summary of the Judgment

The Third Circuit affirmed all convictions. Key holdings include:

• Waiver of Expert CSLI Challenge: A Daubert objection in the first trial did not preserve review where counsel affirmatively waived objections (“no objection”) at retrial under changed factual and evidentiary circumstances.
• Batson & Organizational Affiliation: Striking a prospective juror because of membership in the NAACP was a race‐neutral exercise of peremptory strike; the district court’s thorough, fact‐bound assessment was not clearly erroneous.
• Other Evidentiary Claims: Hamlet waived Jencks Act claims, and no plain error arose from the limited cross‐examination on character evidence under Rules 404(b) and 703.
• Prosecutorial Summation: Reasonable inferences drawn from CSLI testimony do not constitute plain error absent a manifest miscarriage of justice.

Analysis

1. Precedents Cited

• Hoffecker v. United States, 530 F.3d 137 (3d Cir. 2008) – Preservation vs. waiver of evidentiary objections between successive trials.
• United States v. Brito, 979 F.3d 185 (3d Cir. 2020) – Differentiating waiver from forfeiture where counsel’s “no objection” was strategic.
• United States v. James, 955 F.3d 336 (3d Cir. 2020) – Waiver through intentional relinquishment of known rights.
• Daubert framework (Fed. R. Evid. 702) – Admissibility of expert scientific or technical testimony.
• Batson v. Kentucky, 476 U.S. 79 (1986) – Three‐step test for peremptory strikes based on race.
• Snyder v. Louisiana, 552 U.S. 472 (2008) and Flowers v. Mississippi, 588 U.S. 284 (2019) – Deference to trial court’s factual findings on discriminatory intent.
• United States v. Payne, 962 F.2d 1228 (6th Cir. 1992) – NAACP membership as a race‐neutral advocacy group affiliation.
• Guidry v. Lumpkin, 2 F.4th 472 (5th Cir. 2021) – Affiliation‐based strikes and Batson step three.
• Plain‐error review standard for prosecutorial misstatements (United States v. Fulton, 837 F.3d 281 (3d Cir. 2016)).
• Rule 404(b) and character evidence precedents (United States v. Zarintash, 736 F.2d 66 (3d Cir. 1984)).

2. Legal Reasoning

Waiver vs. Preservation: The Court emphasized that “[w]aiver is the intentional relinquishment of a known right.” After an initial Daubert objection to CSLI testimony in the first trial, counsel’s explicit “no objection” at retrial constituted a strategic waiver, foreclosing appellate review of the district court’s discretionary rulings under Fed. R. Evid. 702–705. The panel distinguished unchanged legal questions from shifting factual contexts that demand fresh objections (Hoffecker).

Batson Analysis: On review of the government’s strike of a black juror who disclosed NAACP membership, the Court applied the three‐step Batson framework. It held that:

1. The defense made a prima facie showing of race‐based removal.
2. The government proffered race‐neutral reasons—“juror confidence” and “affiliation with an advocacy organization” challenging mandatory minimums.
3. The district court’s credibility determination—that the affiliation‐based strike was not pretextual—was entitled to clear‐error deference (Snyder).

The panel rejected a per se rule treating any strike of an NAACP member as discriminatory. Instead, it aligned with circuits (e.g., Payne, Hinton) that treat organizational affiliation, even with racial overtones, as a neutral basis when not inherently motivated by race.

Plain Error & Evidentiary Claims: Unpreserved Jencks Act claims were waived when counsel confirmed “no additional Jencks.” Rule 404(b) character evidence and any potential misstatements in closing on CSLI were reviewed for plain error and found harmless in light of overwhelming evidence.

3. Impact

• Trial Strategy & Preservation: Counsels must renew Daubert and other evidentiary objections at each proceeding. “No objection” can constitute waiver under changed circumstances.
• Batson Doctrine Refined: Affiliations with advocacy organizations—even predominantly racial ones—may serve as race‐neutral grounds for strikes if not shown pretextual. Trial courts retain broad deference at Batson step three.
• CSLI Evidence: Affirms use of expert cell‐tower testimony, clarifies that summations may draw reasonable inferences without precise restatements of technical nuances.
• Appellate Review: Reinforces clear‐error deference to district judges’ credibility assessments and highlights the narrow scope of plain‐error intervention in criminal appeals.

Complex Concepts Simplified

• Waiver vs. Forfeiture: Waiver is a strategic, knowing abandonment of a right; forfeiture is the failure to timely assert a right without intent to relinquish.
• Daubert Objection: A challenge under Fed. R. Evid. 702 to the qualifications, methodology or reliability of an expert’s testimony.
• Batson Three Steps:
  1. Defense shows a prima facie discriminatory strike.
  2. Prosecution offers a race‐neutral explanation.
  3. Court decides if the explanation is pretextual (credibility/deference).
• Plain‐Error Review: For unpreserved claims, an error must be clear, affect substantial rights, and seriously undermine trial fairness.
• CSLI Evidence: Data from cell‐tower pings that establish a phone’s general location within a tower’s coverage sector, not precise GPS coordinates.

Conclusion

United States v. Corey Hamlet crystallizes key aspects of appellate practice in criminal cases: the necessity of renewing expert‐evidence objections after evidentiary landscapes shift; the viability of organizational affiliations as race‐neutral grounds for peremptory strikes under Batson; and the high bar for plain-error reversal on both evidentiary rulings and summation content. With its insistence on trial‐level vigilance and deference to district court fact-finding, this precedent will guide counsel and judges in handling expert testimony, juror selection challenges, and efforts to preserve issues for appeal.