After yesterday’s post showing the “thank you” letter I got from Johnnie Cochran for being on the O. J. Simpson defense team, reader “Barffy” decided to call me out by appending this comment to the post.
This isn’t questioning your expert witness contribution. I was surprised that you would tout this letter given it is associated with an appalling miscarriage of justice…the result, without doubt of a completely botched prosecution. The result also, of egregious behavior by the defense.
Are you proud of your involvement?
I already answered Barffy’s question in a post in 2011 about my work for defense counsels on DNA statistics. (I didn’t realize I’d posted Cochrane’s letter before.) This is not an uncommon reaction to my appearing in court to defend accused murderers and rapists, and I try to answer patiently.
When I worked as a defense witness, I never aimed to get anybody “off” whom I thought was guilty. That wasn’t my goal. My goal was always to make sure that when someone’s freedom or life was on the line, they were given a proper defense, and the government not allowed to railroad them by distorting statistics and population genetics. Except in the O.J. case, I always worked for public defenders, who are horribly overworked, underpaid, and have indigent clients who simply can’t afford a good defense. (The budget for public defenders is pathetic.) I always worked for free except for the very first case I took, and then I realized that I didn’t want to even compromise the appearance of my integrity by taking money.
The purpose of a public defender—or any defense lawyer—is to make sure that justice is done: that the state must prove guilt beyond a reasonable doubt. Without forcing the state to do that, the entire principle of our justice system falls down. In contrast, my experience with the prosecution is that they don’t care so much about the system as a whole; rather, they care about getting a conviction. And if they have to do that by cooking or misrepresenting the “match statistics of DNA” then they would—at least when I was doing this kind of work. They want convictions to make them look good and show the public that the bad guys are being locked up.
I explained in the 2011 post what my work was about: making sure that both match statistics and error rates were calculated properly so that the jury could weigh the evidence fairly. It’s another thing, of course, whether a lay jury really has the ability to do that, and in general I think they don’t, for they don’t have an education in population genetics and statistics. (Try giving a jury who doesn’t know what DNA is a complete lesson in Hardy-Weinberg equilibrium and error rates in one afternoon!). But I thought I had to try, because during the time I worked in the courts, both state and the federal government didn’t do it correctly—nor did they care much.
Am I proud of my involvement in the Simpson case? I don’t think “proud” is the right word. “Satisfied” is better: I did what I thought had to be done to make sure that the statistics were used correctly in one of the highest-profile trials of our era. It turns out that there were other issues involved; that the jury didn’t understand all that math; and that there were a ton of ancillary considerations that affected the jury. As for the outcome, I really don’t know how I feel. I think Simpson probably did the murders, but I don’t think the prosecution was terrific at showing it. All I can say is that I’m glad Simpson was convicted of another crime and is now locked up for a long time.
And as for Barffy’s question, I’d answer this way: “You, sir, should be GRATEFUL for a system in which a prosecution is forced to prove its case with proper evidence and is not allowed to railroad someone because ‘everyone knows they are guilty,’ or because prosecutors can bamboozle juries with unsound ‘science’. Until you’ve sat in the witness box as a scientist, and seen the appalling distortions of genetics prosecutors will concoct to convict someone, you shouldn’t pass judgment on what I did.”