Once again, in whose opinion would the testimonies have cleared the defendent? Was the evidence admissable under law? Had the judge blocked questioning along that line? In the professional opinion of the PD, would the testimony have done more harm than good?
(Many lay people often have the idea that if their lawyer would just do things their way, everything will be rosy and perfect, where the lawyer, who knows what is and is not admissable and has a better idea than the defendant what trouble can lead from an imperfectly designed line of questioning. They didn't go to law school for several years for nothing.)