My post on plea bargaining below reminded me of Judge Ralph Adam Fine's (proper) approach to plea bargaining:
During my nine years as a trial judge, I had several defendants who wanted to plead guilty even though when I then asked them to tell me what they did, responded with stories of innocence. When I asked them why they were trying to plead guilty, they all told me that they had been threatened with harsher penalties if they insisted on going to trial. In rejecting their pleas, I told them that we had enough guilty persons to convict, and that we did not need to dip into the pool of the innocent.
In each of the instances, we went to trial and the defendants were acquitted.
Judge Fine proves that plea bargaining is guilty beyond a reasonable doubt in an excellent article he wrote for the Federalist Society; the article is located here (large .pdf).