"A prosecutor has the responsibility of a minister of justice and not simply that of an advocate." See Model Rules of Prof'l Conduct R. 3.8 cmt. 1. Courts have over time consistently expressed serious concerns about prosecutors as witnesses. Generally, when the practice has been allowed, it has been only for compelling reasons in extraordinary purposes. What follows are 3 reasons (according to Justice Sullivan of the 14th District Court of Appeals - Houston) why prosecutors should NOT serve in the dual role of advocate and witness:
1. Confusion of the Trier of Fact - First, the tasks are inherently inconsistent because the function of an advocate is to advance or argue the cause of another, while that of a witness is to state facts objectively. Thus, serving in both roles in the same case could confuse the trier of fact as to whether (and when) the prosecutor is acting in the capacity of advocate, as opposed to witness.
2. Lack of Objectivity - Second, a prosecutor may be unable to participate as a fully objective witness to the extent his interests are aligned with only one of the parties - the State. An experienced prosecutor with an interest in the outcome would be both poised and motivated to wreak maximum strategic damage to the opposition, if permitted to testify. This concern is magnified not only by the serious liberty interests at stake, but also the widely-held perception that a prosecutor, not unlike other law-enforcement officials, may have enhanced credibility with the public.
3. Appearance of Impropriety - Third, the prospect of a prosecutor testifying against the accused raises the appearance of impropriety. It also places a prosecutor in the presumably very uncomfortable – and optically questionable – role of advocating her own credibility or that of a colleague.
* He also lists a fourth reason (on the practical side) - It is difficult for appellate courts to gauge the full impact of the sudden transformation of a prosecutor from advocate into witness.
This post was taken from Justice Sullivan's concurring opinion in Dreyer v. State (HERE). See also the majority opinion here.
Any prosecutors out there disagree with Justice Sullivan's analysis?
(Sorry, no original thoughts on my part - it's been a long Easter weekend)