Human intelligence is derived from human sources. HUMINT remains synonymous to the public with espionage and clandestine activities, yet, in reality, most HUMINT collection is performed by overt collectors such as diplomats and military. HUMINT is the oldest method for collecting information about a foreign power. HUMINT is the primary source of intelligence for all governments until the technical revolution of the mid to late twentieth century. It remains the mainstay of their intelligence collection activities for most nations in the world. HUMINT includes overt, sensitive, and clandestine activities and the individuals who exploit, control, supervise, or support these sources.
Sensitive HUMINT activities may depend upon the same methods as overt activities; however, the sponsor of the activity must be protected from disclosure. Disclosure of the sponsor’s identity may result in political embarrassment, compromise of other intelligence operations, or security threats to the sponsoring nation.
Clandestine HUMINT sources include agents who have been recruited or have volunteered to provide information to a foreign nation and foreign nationals who successfully infiltrate an organization with a cover story. The latter cases are fairly rare and generally come to the United States under the guise of being political refugees. Once in the United States, they move into positions that allow them to gather political, technical, or economic information for their governments.
Even with the explosion of technical capabilities, HUMINT can still provide information that even the most proficient technical collectors cannot, such as access to internal memoranda and to compartmented information. Most importantly, human collectors can provide key insights into the intentions of an adversary, whereas technical collection systems are often limited to determining capabilities. HUMINT can be used to reveal adversary plans and intentions. HUMINT can also provide documentary evidence such as blueprints of facilities, copies of adversary plans, or copies of diplomatic or policy documents. Finally, HUMINT is extremely cost-effective compared with technical collection systems and does not require a significant technological production base for support.