Expert Didn't Blow State's Case

Prosecution witness Dr. Park Dietz. yates 030702 AP

In CBSNews.com Legal Consultant Andrew Cohen's opinion, the testimony of prosecution rebuttal witness Dr. Park Dietz hasn't been earth-shaking up to this point.
The local newspaper and television stations in Houston Friday evening and Saturday morning made hay of the fact that the State’s medical expert, forensic psychiatrist Dr. Park Dietz, refused to offer jurors his opinion of the ultimate issue in the case — whether Yates was “legally insane” at the time of the killings.

It was called a “surprise” that Dietz didn’t take that step on the witness stand to impress upon jurors that he was there to literally solve the case for them on behalf of the State. Even lead prosecutor Joe Owmby conceded after court Friday that it probably was a mistake to have asked Dietz a question that he knew the expert could not or would not answer.

But the whole “Dietz stops short” boomlet now swirling around the trial is a red herring mostly because it suggests that the famed expert was unable or unwilling to deliver the goods for prosecutors. That’s not the case at all. Dietz opined to a “reasonable degree of medical certainty” that Yates knew right from wrong that last June 20th and that ought to be enough to carry the day for the State if — and it’s a big if -- jurors think Dietz is right and the defense experts all were wrong.

Dietz, in other words, didn’t have to answer the ultimate question in favor of prosecutors in order for jurors to conclude that Yates ought to be convicted for drowning her five children last June.

Why is what Dietz said enough to convict? Because the “knowledge or wrongfulness” question is really the only one left unanswered as the case winds down. The other material element of Texas’ insanity statute — whether the defendant had a “mental disease or defect” at the time of the killings — already has been conceded by prosecutors and by Dietz himself.

I suppose Dietz on the witness stand Friday could have told jurors: “Yes, I think Yates was mentally ill last June but I still think she knew what she was doing was wrong so I conclude that she does not meet the elements of Texas’ insanity defense.” And Dietz still may have the opportunity to make such a statement on cross-examination by defense attorneys Saturday.

If nothing else, I suspect prosecutors will ask him why he cannot offer a legal conclusion about insanity in the case, which will give the good doctor an opportunity to tell jurors that it’s not his job to render such a conclusion, it’s theirs.

But if he doesn’t, it’s not the end of the world for the government’s case. Yates’ expert Dr. Phillip Resnick, for example, didn’t exactly offer a rousing conclusion on the issue of legal insanity, either. And prosecutors still can use what Dietz DID say — and the effective way he said it — to permit jurors to reach their own conclusions about Yates’ state of mind at the time.

In fact, it is entirely possible that Dietz didn’t render the ultimate opinion on purpose in order to be able to tell jurors during the next round of questioning that such a statutory conclusion is beyond the province of medical experts. That sort of testimony, of course, would cast a cloud over how far the defense experts went on the witness stand in favor of Yates. Yes, lawyers get that strategic when it comes to such a high-stakes trial and such a high-stakes witness within the trial.

In a case where the State doesn’t deserve much credit for taking a measured approach, it has done the right thing when it comes to fighting over the issue of Yates’ insanity. Prosecutors would have lost a lot of credibility with jurors had they stood up in court and tried to argue that Yates did NOT have a mental illness last June. All the medical records suggest otherwise and even Dietz couldn’t swim against that tide.

What they do by limiting their focus to the “wrongfulness” question is to maintain credibility with jurors and fight the fight on the best ground they have in this case. And that ground is certainly the evidence that Yates knew — from the time she waited until her husband left the house that awful morning until the moment she dialed 911 after the killings were done — that she was doing something wrong in the eyes of the law, society and God, as Dietz put it.

Dietz may not have “won” the case for prosecutors on Friday and his role in this trial continues Saturday during what ought to be fairly combative cross-examination. But contrary to what you might think, he didn’t “lose” the case for the State either.

By Andrew Cohen
By Andrew Cohen
  • John Esterbrook

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