Logan v. State
In Logan v. State, 43 Wis. 2d 128, 137, 168 N.W.2d 171 (1969), the defense attorney, confused about the difference between admissible corroboration testimony and procedurally inadmissible alibi testimony, withdrew a key witness who would have corroborated the defendant's version of events. See Logan, 43 Wis. 2d at 136.
The court was therefore presented only with the conflicting testimony of the accuser and of Logan, and found Logan to be less credible. See id.
The Court concluded that even though it was defense counsel who had excluded the admissible corroboration evidence, the exclusion was prejudicial because the credibility of Logan was a major factor in the determination of guilt or innocence; thus, a new trial in the interests of justice was warranted. See Logan, 43 Wis. 2d at 136-37.