As a criminal defense lawyer sometimes we get cases where we have pretty good but not overwhelming evidence that our client is innocent.
In some counties, I contact the prosecutor and explain the evidence. Sensible prosecutors will agree to a deal where my client pleads guilty to a lesser offense that's better than the original charge. Yes ideally it would be dismissed but this compromise tends to make everyone happy.
Then there are counties where the District Attorneys have strict plea bargaining policies.
An example is a recent DWI case where we had great evidence. Police documents indicated our client may not have been driving (something they have to prove beyond a reasonable doubt). On video, one of the cops said he was surprised the breath test result was so high because our client seemed sober. And he looked and sounded completely sober. This took place in a county where the DWI has a strict policy on plea bargaining for DWI cases. Due to policy, the only offer was for our client to plead to the charge (link is to a previous post about such policies).
A reduction to DWAI would have been reasonable and my client would have accepted it. I'd prefer a dismissal or a better deal of course, but it would have been reasonable.
Since that was not possible, we did not discuss the evidence with the DA. We simply prepared for trial. When trial came, the flaws suddenly became apparent and the case was dismissed.
The policy led to a lot of waste. My client spent a lot of time and money. The judge and court staff wasted time. So did the prosecutors. If they made deals on cases like this, they'd have more time for the stronger and more important cases. This is a DA's office that has blown some big ones.
Perhaps the worst, about 30 prospective jurors sat in court for hours.
I appreciate the concern about drunk drivers. Through my work I've seen the harm more than most. But the punitive approach is wrong, especially with defendants who have clean records. The focus should be getting drunk drivers off the road and into treatment. Plea bargaining accomplishes that.