The trial I’ve been reading about made me wonder: Is it better for the defense to offer a theory - any theory - of what may have happened than to say they have no way of knowing what happened (because their client wasn’t there, being innocent and all) and just emphasise the inconclusive nature of each individual piece of circumstantial evidence?
Linky for the curious, but in a nutshell: the defence say she must have gone for a Zoloft-haze-induced 2am walk for 14km, and fallen or jumped off a bridge, either as a suicide or accident. Prosecution say she was murdered by her husband for $900,000 life insurance which would save his floundering business and free him to be with his long time mistress. Autopsy inconclusive.
You could argue that the job of the prosecution is to prove guilt beyond a reasonable doubt, and the job of the defense is to introduce that doubt. However, arguing “maybe this is what happened” can blow up in your face if the prosecution shoots down all of your theories. “Maybe they’re hiding something… like GUILT.”
At least in the US it is totally up to the prosecution to prove guilt. The defense doesn’t have to do anything at all to introduce doubt - they can sit there quietly, not say a word, call any witnesses, introduce any evidence, etc. and that is absolutely fine and the jury cannot use “lack of evidence of innocence” during deliberations. I finished up my second stint on jury duty late last year and that’s pretty much what the defense did during the trial, and the judge (plus both sets of attorneys) took great care to point out that the burden is ENTIRELY on the prosecution to make their case.
Of course if the defense thinks that the prosecution’s case has holes in it they may want to try and show that but as you said, that does carry a risk of backfiring - defense witnesses and evidence introduced during the trial can be cross-examined/picked apart by the prosecution and maybe something won’t show what the defense intended it to. The defense attorney might instead opt to wait until closing arguments and basically tell the jury “We don’t think the prosecution proved their case beyond a reasonable doubt, here is why”; the closing statements aren’t evidence and it’s a good time to put the seeds of doubt into the jury’s mind (and remind them of the substantial burden of proof that the prosecution has to meet).
I couldn’t understand why the defence would even bother trying the stupid story about her going for a walk in the middle of the night and jumping off a bridge because her brother in law’s baby son had been born that morning and she’d always wanted a son, so maybe she took too much Zoloft and developed serotonin syndrome. It seems so improbable. Why not just say “We don’t know what happened. She was alive, he went to bed, he woke up and she was gone, and weeks later she was found under the bridge. We can’t ask her what happened while he was sleeping, so we’ll never know.”?
Thinking about it more, most of the defence witnesses were the accused’s family and friends, and they testified about the victim’s severe depression, focusing on her post natal depression in 2005. Maybe they wouldn’t have been allowed to do that if they didn’t explicitly tie it to her death? And without it all they’ve got is stuff like “Yes, multiple expert witnesses testified that the marks on his face are more consistent with fingernail scratches than with the razor cuts he claims them to be, but they couldn’t rule out the razor with 100% certainty!”, and that’s a pretty weak gotcha. They’ve never suggested someone else was involved, except to talk up the volatile nature of the mistress a bit during questioning (not mentioned in closing AFAIK). Possible suicide or disorientation from anti depressants is about all they’ve got.
Juries (like people in general, because they are made up of people in general), love to have explanations for things. Even though they’re pretty good about the high-concept reasonable doubt stuff, it can definitely help to put a face on their doubt if they have a “but what about?” narrative provided for them.
There is a conceptual line that divides alternate theories that are plausible enough from those that aren’t plausible enough. If I give you an alternate theory for who took the cookies that is obviously total bullshit, that will actually have the effect of making you more certain that I took them, because why else am I fabricating this bullshit story? If I give you an airtight alternate theory that is extremely credible and explains the evidence better than the notion that I did it, that will obviously have the effect of making you much less certain that I did it. In the grey areas in between those two poles, there’s a space where my theory doesn’t actually convince you that my guilt is no longer the most likely explanation, but it does weaken your certainty. You think I still probably did it, but maybe now it’s 80% instead of 95%.
That’s the important space, because it plays on the jury’s twin discomforts: one with a total lack of narrative, and one with totally rejecting something that’s possible. Hmm, yeah, I guess that could have happened. Is that reasonable? Is it doubt? Oh shit.
The question is, how plausible does my theory have to be before it stops triggering the first effect and starts to at least erode your confidence that I did it? The worse the case looks for the defendant, the bigger a risk the lawyer’s going to be comfortable taking with that line.
An alternative defense scenario usually works best when there is a simpler, easier to understand theory, than what the prosecution is pitching.
i.e., the hot car dead baby case - it’s easier to think that a father would be absent minded and forget his baby is in the car than that a father would deliberately roast his own son to death.
Convoluted bizarre theories typically don’t play well to juries.
Strategic decisions are very fact specific. Depending on what happened, the defense may offer an alibi, claim self-defense, seek to suppress evidence/argue failure of proof, etc. There is no “one size fits all” strategy for criminal defense. Every case is different, and requires a unique approach.