## Facts

- Willie DeCoster, Jr. was prosecuted in the District of Columbia for armed robbery and assault with a dangerous weapon arising from a street robbery involving three assailants.
- The victim testified he was restrained from behind, threatened with a razor, and robbed of a wallet containing over $100.
- Two plainclothes officers observed the robbery, gave chase, and one officer pursued DeCoster from the scene into a hotel where he was arrested at the lobby desk.
- The victim later suffered a serious car accident that impaired his memory and eyesight; at trial he could not identify DeCoster or the razor allegedly used.
- A jury convicted DeCoster; he challenged the conviction on Sixth Amendment grounds, alleging inadequate investigation and preparation by defense counsel.
- In an earlier appeal, the court remanded for an evidentiary hearing on ineffective assistance (United States v. DeCoster, 487 F.2d 1197 (D.C. Cir. 1973)).
- After further proceedings, the D.C. Circuit reheard the case en banc to clarify the governing ineffective-assistance standard and the role of prejudice.

## Issues

1. What constitutional standard governs whether defense counsel’s pretrial investigation and preparation were so deficient as to deny effective assistance of counsel.
2. Whether a defendant must affirmatively prove prejudice from counsel’s deficiencies, or whether prejudice may be presumed or the burden shifted to the government.
3. Whether DeCoster showed prejudice sufficient to warrant reversal of his convictions.

## Decision

- The en banc court affirmed DeCoster’s conviction.
- The controlling opinions adopted a “reasonably competent assistance” benchmark, measured against the range of competence demanded of criminal defense attorneys.
- The court rejected automatic reversal or a categorical presumption of prejudice based solely on deficient performance.
- The court required a showing that counsel’s deficiencies likely affected the outcome or otherwise undermined confidence in the verdict.
- Applying that approach, the court concluded DeCoster did not demonstrate that alleged investigative omissions had a probable effect given the officers’ eyewitness pursuit and other evidence supporting the verdict.

## Legal Principles

- The Sixth Amendment guarantees effective assistance of counsel, which includes a duty to conduct reasonable investigation or make a reasonable strategic decision that further investigation is unnecessary.
- Deficient performance is assessed by reference to reasonable professional judgment and the competence ordinarily demanded in criminal cases; counsel need not be error-free.
- Ineffective assistance does not mandate reversal absent prejudice; courts do not automatically presume prejudice from attorney error outside narrow circumstances.
- The defendant bears the burden to show prejudice—i.e., that the identified deficiencies had a likely effect on the outcome or materially undermined confidence in the verdict.

## Conclusion

The D.C. Circuit held en banc that ineffective assistance requires both deficient performance and a demonstrated prejudicial effect on the verdict, and it affirmed DeCoster’s conviction because he failed to show that counsel’s alleged investigative shortcomings probably changed the trial outcome.


United States v. DeCoster, 624 F.2d 196 (D.C. Cir. 1979) (en banc)