Because the agency authority of both parties comes from the entrustment of the parties. Principal-agent refers to an agent who has the power of agency based on the authorization of the principal. China's civil procedure law stipulates that when entrusting others to represent litigation, a power of attorney signed or sealed by the client must be submitted to the people's court. The power of attorney must specify the entrusted matters and authority. An agent ad litem must have the special authorization of the client, and can admit, waive or change the claim, make a settlement, file a counterclaim or appeal on his behalf.
Two, in criminal proceedings, the difference between the two is relatively large:
According to the provisions of the Criminal Procedure Law, defense lawyers may collect materials related to this case from witnesses or other relevant units and individuals with their consent; With the permission of the people's procuratorate or the people's court, and with the consent of the victim or his close relatives or witnesses provided by the victim, the defense lawyer may collect materials related to the case from them. Defenders with general status do not enjoy the latter two rights stipulated in the law. As a defender, a lawyer has the right to consult the case file in addition to the rights of the general defender, and other defenders must obtain the permission of the court to exercise this right. In addition, only lawyers can be hired as defenders in the investigation stage. Therefore, lawyers do not appear as lawyers, just like ordinary people.