I know your frustration. Problem is, some very sharp attorney will use the argument that, when his client started drinking, he had no intent to operate a vehicle. At the time he operated the vehicle, he was so intoxicated that he was not mentally competent to make the decision to drive / not drive. Thus, he is not guilty by reason of temporary mental incompetence. Don't laugh! Silly as this sounds, this is the kind of shit attorneys use to get their clients off. Remember, they only need to convince one person to hang a jury.