http://thecriminallawyer.tumblr.com/post/16202923895/interlu...
In short, you're asking jurors to take on a huge responsibility with little to no understanding of the laws they're being expected to make a decision on. In virtually every instance the jurors are left in a completely uneducated state and unable to give any proper assessment, relying basically on whatever cues they decide to pick up on instead of factual evidence. The idea of 12 Angry Men never really existed with juries and was far outside the scope of what a juror is really supposed to be doing.