I know Rule 704 states that an expert can testify on the "ultimate issue" in a case. However, there seem to be some limitations on this, and on just how far this rule is to be interpreted. Can a psychiatrist testify whether, in his opinion, the defendant acted in self-defense?

The clock is ticking on our trial.

The latest trend in expert testimony is to grab a psychiatric type and get them to testify that the defendant's version of events is true. Of course, they don't say exactly that. They just nod knowingly and give the defense version some important sounding title.

But even the defense must point to some accepted field of research for that field. And the field of research must be accepted as reliable in the forensic world. Just because there are a bunch of psychiastrist types that talk about it doesn't mean it is admissible in a criminal case.

So, the question to the expert should be: what body of research can you show that accepts your type of opinion as reliable in criminal trials?

Also, never forget that the expert's knowledge must assist the trier of fact to understand the evidence or to determine a fact in issue. If the law of self-defense is so complicated that only an expert can determine when and to what degree force should be used maybe we need to rethink sec. 9.31.

The judge said no, although, of course, the psychiatrist can testify about various psychiatric issues.