## Facts

- Samuel Herrera supplied marijuana to multiple street-level dealers in Oklahoma City, including Michael Caldwell.
- Caldwell’s first transaction with Herrera involved multi-kilogram marijuana on consignment, followed by repeated multi-kilogram deliveries over roughly two years.
- David Anderson was a marijuana dealer and friend of Caldwell. Early in their friendship, Anderson sold small amounts of marijuana to Caldwell a few times, then stopped selling to him.
- About a year later, Anderson needed a new supplier and asked Caldwell for a lead. Caldwell introduced Anderson to Herrera and was present at their first meeting.
- Caldwell received no payment for the introduction and played no further role in Anderson’s later purchases from Herrera.
- After the introduction, Herrera supplied marijuana separately to Caldwell and to Anderson.
- The government charged Caldwell with conspiracy to distribute marijuana and alleged a single, three-person conspiracy (Herrera–Caldwell–Anderson). To reach the charged threshold of at least 100 kilograms, the government aggregated Herrera’s sales to Caldwell and Herrera’s sales to Anderson.
- Caldwell admitted he conspired with Herrera and did not dispute that Herrera conspired with Anderson, but challenged whether the proof showed one overarching conspiracy joining all three men.
- A jury convicted Caldwell. The district court sentenced him using a drug quantity that included marijuana Herrera sold to Anderson, based on the jury’s finding of a single conspiracy.
- On appeal, Caldwell argued (1) the evidence was insufficient to prove a single tripartite conspiracy and the related quantity finding, and (2) the district court erred by admitting evidence of his prior drug convictions under Federal Rule of Evidence 404(b).

## Issues

1. Whether the evidence was sufficient for a rational jury to find one overarching conspiracy among Herrera, Caldwell, and Anderson (rather than separate conspiracies), permitting the aggregation of Herrera’s marijuana sales to Anderson as attributable to Caldwell.
2. Whether the district court abused its discretion by admitting evidence of Caldwell’s prior drug convictions under Federal Rule of Evidence 404(b), and if so, whether any error required reversal.

## Decision

- The Tenth Circuit affirmed Caldwell’s conspiracy conviction.
- The court held the evidence supported a conspiracy between Caldwell and Herrera and also supported a separate conspiracy between Herrera and Anderson.
- The court held the evidence was insufficient to prove a single, three-party conspiracy linking Caldwell to Herrera’s later distribution to Anderson; a one-time introduction and parallel purchasing from a common supplier did not show a shared agreement to jointly distribute marijuana.
- Because the jury’s drug-quantity finding and the sentence were based on the existence of a tripartite conspiracy, the court ruled that quantities tied only to the Herrera–Anderson conspiracy were wrongly attributed to Caldwell.
- The court vacated Caldwell’s sentence and remanded for resentencing based on drug quantity attributable to the Herrera–Caldwell conspiracy.
- The court rejected Caldwell’s challenge to the admission of his prior drug convictions (or found any error harmless in light of other evidence of Caldwell’s knowing participation in the Herrera conspiracy).

## Legal Principles

- Proof of conspiracy requires an agreement to work together toward an unlawful objective; repeated buyer–seller transactions may support a conspiracy finding when the evidence shows coordinated distribution activity rather than isolated purchases.
- The existence of a common supplier does not, by itself, establish a single conspiracy among multiple customers; separate dealer–supplier relationships can be separate conspiracies.
- A defendant is not accountable for drug quantities distributed in a separate conspiracy involving the same supplier unless the government proves the defendant joined a single, shared agreement covering that distribution.
- On sufficiency review, the appellate court views the evidence in the light most favorable to the government and asks whether any rational juror could find the elements beyond a reasonable doubt; that standard still requires evidence linking the defendant to the charged scope of the conspiracy.
- Evidence of prior convictions offered under Rule 404(b) is reviewed for abuse of discretion and must be admitted for a proper non-propensity purpose with appropriate balancing against unfair prejudice; even if admission is mistaken, reversal is not required if the error did not affect the verdict.

## Conclusion

United States v. Caldwell held that the government proved Caldwell conspired with Herrera to distribute marijuana, but failed to prove Caldwell was part of a single conspiracy that also included Herrera’s later marijuana distribution to Anderson; the conviction was affirmed, the sentence was vacated, and the case was remanded for resentencing without aggregating drug quantities from the separate Herrera–Anderson conspiracy.


United States v. Caldwell, 589 F.3d 1323 (2009)