Domestic intelligence services are the only organization that is capable of performing counterintelligence  Domestic intelligence services are the only organization that is capable of performing counterintelligence. They have the capacity and the authority to detect foreign spies in the national jurisdiction, and experience with local surveillance and investigation. Part of the job of domestic intelligence is to maintain a network of informers and agents, and this can be used to find and track foreign intelligence services on a mission – these functions can’t be easily performed by the military or foreign intelligence so an independent domestic intelligence agency is necessary.