Even innocent people need to have a criminal defense attorney.
Criminal defense attorneys know that the legal system is skewed against the accused. The police are not motivated to assist the accused. The prosecutor is not on the side of the accused. The judge is not trying to help the defendant. If a case ends up in court, the accused will be up against the police, the prosecutor, and the judge. All these parties have legal training and may be motivated to sink the defendant. The accused needs to have someone on his side. That is the responsibility of the criminal defense attorney.
It is naive to believe that a person will get a fair shake in our legal system without a savvy criminal defense attorney at his side.
The law is complicated. People sometimes feel they are innocent, when in fact the law may view them as guilty. The criminal law has many pitfalls for the unaware. Tactical and strategic decisions are made in the course of a criminal prosecution which may be bewildering to the average person. Words are used in our legal system which have a meaning contrary to their ordinary usage. An innocent person needs an excellent attorney at his side in order to have a fair chance of beating a criminal charge.