The article examines enormous disadvantages which plaintiffs in excessive force cases must overcome to prevail, such as police credibility and jurors' simplistic conception of policing. A discussion of police defendants' belief that they are invulnerable against liability focuses on misplaced faith in the split-second syndrome, the feeling that since no two street situations are alike, it is impossible to train officers in other than very broad tactical skills. The paper reviews issues involved in the selection and work of police experts. While such witnesses offer opinions about the actual incident, they must also analyze related supervisory and training practices. The key question is the extent to which unreasonable police action has been made predictable by gross administrative failures. Areas examined include the department's official reaction to the incident, the officers' career histories, departmental history, and training. 15 footnotes.