That doesn’t sound like justice; why doesn’t the prosecutor just do the trials?
Trials are both time-consuming and expensive. For the government to conduct a trial for even a relatively minor traffic offense can require a trial by jury, involving eight jurors and several witnesses. Such a trial can take a day or more to conduct, and the government must pay the jurors, the judge, the prosecutor and the police officers’ salaries or overtime. In 2008, 225,301 criminal misdemeanor and traffic cases were filed in the Franklin County Municipal Court alone. That court has 15 judges and about 30 prosecutors, and the prosecutors and judges handle civil cases as well. It would not be possible for the government to try all 237,061 cases in a year, so plea bargaining is one way to make sure violations of law are addressed, given the limited prosecutorial and judicial resources available.