## Facts

- DEA agents arranged a controlled purchase of crack cocaine from Clyde Tse in Mattapan, Massachusetts using Stephen Williams, a cooperating witness.
- Before the buy, agents searched Williams and his car to confirm he had no drugs or money, gave him $450, and outfitted him with an audio transmitter (“kel”) that allowed agents to listen and record but not communicate with him.
- Williams went to Tse’s residence and spoke with Tse about buying a half ounce of crack for $450; agents recorded this initial conversation, including Tse telling Williams to return shortly.
- Williams met again with agents and then returned to Tse’s residence about 40 minutes later.
- When Williams returned, Tse was on the phone and then told Williams “we’re on” and directed him to drive “just around the corner.”
- As Williams drove away with Tse, agents lost the kel signal and could not record what happened next; an agent later saw Williams’s car parked nearby.
- Williams eventually returned to the agents with crack cocaine and without the $450, and Tse was charged with distribution under 21 U.S.C. § 841(a)(1).
- At trial, because the government could not record the actual exchange, it relied heavily on Williams’s testimony along with corroboration from searches, surveillance, and the recorded initial conversation.
- Tse sought to impeach Williams with a prior conviction for assault and battery on a police officer (ABPO). Tse also had a prior ABPO conviction; the government sought to use it if Tse testified.
- The district court excluded both ABPO convictions, reasoning that the admissibility analysis for one was closely tied to the other, but permitted other impeachment of Williams (including other criminal conduct and his drug involvement).
- The district court also admitted evidence of a later drug transaction involving Tse and Williams (February 2, 1999) as other-acts evidence, and instructed the jury on the limited purpose for which it could consider that evidence.
- A jury convicted Tse, and he appealed the limits on impeachment, the admission of the later transaction, the adequacy of limiting instructions, and related evidentiary rulings.

## Issues

1. Whether the district court erred under Federal Rule of Evidence 609 and the Sixth Amendment Confrontation Clause by excluding Williams’s ABPO conviction as impeachment of the government’s key witness.
2. Whether the district court erred under Federal Rules of Evidence 404(b) and 403 by admitting evidence of a subsequent drug transaction to show intent and knowledge, and whether the limiting instructions were adequate.
3. Whether additional limits on impeachment and the admission of parts of Williams’s testimony denied Tse a fair trial.

## Decision

- The First Circuit affirmed Tse’s conviction for distributing cocaine.
- The court held the district court did not abuse its discretion, and did not violate the Confrontation Clause, by excluding Williams’s ABPO conviction where the jury still heard substantial impeachment material and where the ruling was connected to the potential admission of Tse’s similar conviction.
- The court upheld admission of the February 1999 transaction under Rule 404(b) as relevant to intent and knowledge, and found the district court’s Rule 403 assessment and limiting instructions sufficient to address unfair-prejudice concerns.
- The court rejected Tse’s remaining evidentiary challenges, concluding that the limits on cross-examination were within the trial court’s authority and that any arguable error did not warrant reversal on the record as a whole.

## Legal Principles

- Under Rule 609(a)(1), trial courts apply different balancing considerations depending on whether the conviction is offered to impeach the accused or another witness, and the trial judge has broad discretion in managing that balance.
- The Confrontation Clause guarantees an opportunity for effective cross-examination, not cross-examination on every desired topic; reasonable limits are permitted to avoid unfair prejudice, confusion, or cumulative proof so long as the jury has enough information to assess credibility.
- Rule 404(b) permits admission of other acts, including later acts, for non-character purposes such as intent and knowledge; such evidence remains subject to Rule 403’s requirement that probative value not be substantially outweighed by unfair prejudice.
- Limiting instructions are a key tool in controlling the jury’s use of other-acts evidence, and appellate courts generally presume juries follow them absent a strong reason to think otherwise.
- Appellate review of evidentiary rulings is deferential; reversal typically requires a showing that an abuse of discretion affected substantial rights rather than harmless error.

## Conclusion

United States v. Tse affirmed a cocaine distribution conviction where the government relied heavily on a cooperating witness because the controlled-buy recording failed during the actual exchange; the First Circuit held that excluding the witness’s ABPO conviction did not violate Rule 609 or the Confrontation Clause given the other impeachment allowed and the linked risk of admitting the defendant’s similar conviction, and it upheld admission of a later, similar drug transaction under Rule 404(b) for intent and knowledge with limiting instructions and a reasonable Rule 403 balance.


United States v. Tse, 375 F.3d 148 (2004)