Plea bargaining is extremely difficult in jurisdictions based on civil law. Unlike common law systems, civil law systems have no concept of plea. If the defendant confesses in a civil law system, that confession is simply entered into evidence, but the prosecution is not absolved of the duty to present a full case. Also, unlike common law systems, prosecutors in civil law countries have limited or no power to drop or reduce charges once a case has been filed, and in some countries their power to drop or reduce charges before a case has been filed is limited. Many civil law jurists find the concept of plea bargaining to be abhorrent.
The reasons for plea bargains may be several. In most cases, the plea bargain is to avoid the uncertainty of the jury trial. Prosecutors generally have wide discretion as to the charges they may bring, and therefore tend to charge the defendant with the most extreme charges that are applicable to the situation at hand. The defendant then is left to choose between the certainty of a much less serious charge, or the uncertainty of a jury trial in which the defendant may be found not guilty or may be found guilty of a much more serious charge.
In other cases, a defendant may have culpability with others in a criminal matter and at the same time have knowledge which will ensure the success of a broader or more significant prosecution. In such a case, in order to secure the defendant's willingness to testify for the prosecution in other cases, charges or sentencing in his own case may be offered to be lessened if he does, indeed cooperate fully with the prosecution.
In still other cases, prosecutors may be convinced that they have the right defendant and a completely accurate charge as to what crime(s) he committed, and yet the evidence to secure a conviction may be questionable or lacking. It is of benefit to both parties (prosecutor and defendant) to arrange a resolution of the matter without either side taking the chance that the case, once submitted fully to a judge jury, would go completely against them.
It has been argued that the American criminal justice system would simply cease to function without plea bargaining, and that it forms a framework wherein the accused and his accusers can reach an agreement which settles the case once and for all, in what is hoped will be a spirit of fairness.
Critics of the system point out that the plea bargain system puts strong pressure on defendants to plead to crimes that they know that they did not commit, and that the outcome of a plea bargain may depend strongly on the negotiating skills and personal demeanor of the defense lawyer, which puts persons who can afford good lawyers at an advantage. Furthermore, the system encourages prosecutors to overcharge at the start of a case which leads to caseload pressures. Finally, many jurists, especially in civil law nations, find the notion of plea bargaining contrary to the purpose of the law in which a specific action should be associated with a specific penalty.