The vast majority of criminal cases are resolved by guilty pleas to some charge, often a reduced charge or one with a plea agreement. Does this mean that the criminal justice system is corrupt? No problem. Nor does it mean that the criminal justice system is not fair.

In cases that go to trial, the judge does not assume that the officer is telling the truth because he or she is an officer, but rather because of past experience. These people see each other at least several times a week, so there is an underlying set of relationships at work. Just because a citizen disagrees with an officer, the result is not disbelief in the citizen’s statement.
 
The judges understand very well that everyone sees every situation from a slightly different perspective, and that you can be absolutely sure of your correctness and yet absolutely wrong, or the officer may be sure that it was you who was speeding and , however, has only been pointing a hair. off on the radar gun and focused on another vehicle. It is the assertion that the officer is lying (instead of being wrong) that can create a problem. Unless the officer has a history of lying in court, it is seldom advantageous to claim that he is doing so. At my first law firm, we were absolutely certain that police in Columbus, Ohio were throwing crack cocaine at the feet of black men standing on street corners (likely as lookouts for a drug ring) to justify their arrest, but they were never able to do so. tape, so we never made the charge.
 
However, one does not need to plead guilty to any criminal charges or accusations. Most charges can be resolved by a guilty plea to some intermediate offense. For example, an amendment of a traffic violation to an equipment violation is usually possible. I don’t recall ever convicting a client of anything other than a reduced charge. While plea bargaining is immoral (those who are guilty must be found guilty), it is necessary as a key component of the criminal justice system.

See, for example, Palermo, White, Wasserman & Hanrahan (1998), who estimate that 90-95% of all guilty pleas by persons represented by counsel are the result of plea deals (p. 112). For more serious charges, there is a big difference between attitudes in different states. I find Ohio judges will negotiate anything; the culture in Kentucky is that the judge will accept a plea deal only if the facts require it; the judge will really investigate, in the file and in public hearing, why said agreement should be accepted.
 
Of course, even in the northern states I’ve usually been able to show some significant weakness in the prosecution’s case, but that’s largely because I do a lot of casework and can often find some key facts that are they would have missed if my motivation was less. Or maybe I’ve just had a string of innocent clients.
 
Reference:
 
Palermo, GB, White, MA, Wasserman, LA, & Hanrahan, W. (1998). Plea Bargain: Injustice for All? International journal of criminal therapy and comparative criminology.