They are to present all evidence to rebut the prosecutor's arguments, they challenge the procedural errors and may seek to have some charges dropped due to insufficient evidence of the crime.
Their main goal is to obtain the complete dismissal of the charges brought against their client or obtain a not guilty ruling by the jury of their peers or the judge. The criminal justice system is a 3 part system which includes the judge and jury, the prosecutor, and the defence lawyer. Each part of the system is there in order to prevent abuse of power, and make sure each person receives a fair and equal trial. If the accused did not have a defense attorney they would have noone to fight for them and their rights, this would cause the system to be even more corrupt and unbalanced, as every person presented to the court would already be guilty because they have no one to show the contradicting evidence in their
favor. Kaffee was a good defense lawyer for this complicated case. He was able to get the truth out of col. Jessup , this was that he indeed did order the code red. If kaffee was acting as a defense attorney in a civil case he would not be appointed by the government by law as a right, but would only represent the person if they paid to have him there. The movie did sensationalize the court seen to add excitment to the seen, there was alot of tension during the questoning process, the famous “i want the truth” “you cant handle the truth scene happend during this trial.