The origins of the expression is to be found in its initial use by Marshal Hubert Lyautey, the main theoretician of French colonial warfare and counterinsurgency strategy. The oil spot approach was later one of the justifications given in the Pentagon Papers for the Strategic Hamlet Program. Cordon and search Cordon and search is a military tactic, one of the basic counterinsurgency operations in which an area is cordoned off and premises are searched for weapons or insurgents. Other related operations are "Cordon and knock" and "Cordon and kick". "Cordon and search" is part of a new doctrine called Stability and Support Operations or SASO. It is a technique used where there is no hard intelligence of weapons in the house and therefore is less intense than a normal house search. It is used in urban neighborhoods. The purpose of the mission is to search a house with as little inconvenience to the resident family as possible. Air operations Air power can play an important role in counterinsurgency, capable of carrying out a wide range of operations: Transportation in support of combatants and civilians alike, including casualty evacuations; Intelligence gathering, surveillance, and reconnaissance; Psychological operations, through leaflet drops, loudspeakers, and radio broadcasts; Air-to-ground attack against 'soft' targets. Public diplomacy In General David Petraeus' Counterinsurgency Field Manual, one of the many tactics described to help win in counterinsurgency warfare involves the use of public diplomacy through military means. Counterinsurgency is effective when it is integrated "into a comprehensive strategy employing all instruments of national power," including public diplomacy. The goal of COIN operations is to render the insurgents as ineffective and non-influential, by having strong and secure relations with the population of the host nation. An understanding of the host nation and the environment that the COIN operations will take place in is essential. Public diplomacy in COIN warfare is only effective when there is a clear understanding of the culture and population at hand. One of the largest factors needed for defeating an insurgency involves understanding the populace, how they interact with the insurgents, how they interact with non-government organizations in the area, and how they view the counterinsurgency operations themselves. Ethics is a common public diplomacy aspect that is emphasized in COIN warfare. Insurgents win their war by attacking internal will and the international opposition. In order to combat these tactics, the counterinsurgency operations need to treat their prisoners