The goal of this study is to ascertain how Thailand wages counterinsurgency (COIN). Thailand has waged two successful COINs in the past and is currently waging a third on its southern border. The lessons learned from Thailand’s COIN campaigns could result in modern irregular warfare techniques valuable not only to Thailand and neighboring countries with similar security problems, but also to countries like the United States and the United Kingdom that are currently reshaping their irregular warfare doctrines in response to the situations in Afghanistan and Iraq. The first set of COIN lessons comes from Thailand’s successful 1965-85 communist COIN. The second set comes from Bangkok’s understudied 1980s-90s COIN against southern separatists. The third set comes from Thailand’s current war against ethnic Malay separatists and radical Islamic insurgents attempting to secede and form a separate state called “Patani Raya,” among other names. Counterinsurgency is a difficult type of warfare for four reasons: (1) it can take years to succeed; (2) the battle space is poorly defined; (3) insurgents are not easily identifiable; and (4) war typically takes place among a civilian population that the guerrillas depend on for auxiliary support. Successful COINs include not only precise force application operations based on quality intelligence, but also lasting social and economic programs, political empowerment of the disenfranchised, and government acceptance of previously ignored cultural realities. Background: In 1965, communist insurgents, backed by the People’s Republic of China and the Democratic Republic of Vietnam (North Vietnam), began waging an insurgency against Thailand in order to overthrow its government and install a Marxist regime. The Thai government struggled, both politically and militarily, to contain the movement for years, but eventually, it prevailed. Its success was based on a combination of effective strategy and coordination, plus well-designed and run security, political, and economic programs, the latter nowadays called the “three pillars of COIN,” a phrase developed by David Kilcullen, a modern COIN theorist and practitioner. One of Bangkok’s most successful initiatives was the CPM program (civil-military-police), which used a linked chain of local forces, police, and the military to not only provide security for villages, but also economic aid and administrative training to rural peoples. State political programs that undercut communist political programs backed by masterful diplomacy and a constant barrage of rural works helped erode the communist position. The 1980s-90s COIN against southern separatists followed similar lines. The far South’s four border provinces, comprised of 80 percent ethnic Malay Muslims, had been in revolt on and off for decades since Bangkok annexed the area in 1902. Bangkok had waged haphazard COIN campaigns against rebel groups there for decades with mixed results. But after the successful communist COIN was up and running in 1980, Bangkok decided to apply similar ways and means to tackle the southern issue. The government divided its COIN operations into two components: a security component run by a task force called CPM-43, and a political-economic component run by the Southern Border Provinces Administrative Center, or SB-PAC. SB-PAC also had a Special Branch investigative capacity. Combined, the 80s-90s southern COIN strategy relied on extensive military intelligence networks to curb violence, civilian administrators to execute local political reforms, and local politicians to apply traditional Malay and Muslim problem solving techniques to keep the peace. These programs worked well against the multitude of southern insurgent groups that conducted sporadic attacks against government and civilian targets while also running organized criminal syndicates. By the end of the 1990s, with a dose of Thailand’s famed diplomacy and help from Malaysia’s Special Branch, Bangkok defeated the southern separatists. In January 2004, however, a new separatist movement in southern Thailand emerged – one based on ethnic Malay separatism and radical Islam. It is a well-coordinated movement with effective operational expertise that attacks at a higher tempo than past southern rebel groups. It moreover strikes civilian targets on a regular basis, thereby making it a terrorist group. Overall, it dwarfs past southern movements regarding motivation and scale of violence. Thai officials think the Barisan Revolusi Nasional Coordinate, or BRN-C, leads the current rebellion, but there are several other groups that claim to also lead the fight. Members of the insurgency are nearly exclusively ethnic Malays and Muslims. The movement demonstrates radical Islamic tendencies thought its propaganda, indoctrination, recruitment, and deeds. It is a takfiri group that kills other Muslims who do not share its religious beliefs, so it wrote in its spiritual rebel guidebook, Fight for the Liberation of Patani. BRN-C seeks to separate the four southernmost provinces of Pattani, Yala, Narathiwat, and Songkhla from Thailand in order to establish an Islamic republic. The separatists base their revolt on perceived military, economic, cultural, and religious subjugation going back to the early 1900s. And they have a point. The central government has, at different times in the past, indeed treated southerners with tremendous disdain and sometimes violence – especially those considered insurgents. But Bangkok has also instituted scores of economic and social aid programs in the south – mosque building, college scholarships, and medical aid, for example – so it has not been a continual anti-Muslim “blood fest” as government detractors have painted it. Still the maltreatment, certainly many times less than yesteryear, has provided today’s insurgents with ideological fodder for a steady stream of recruits and supporters. Combined with radical Islam, it has bonded the insurgents to a significant degree. Statistically, in the 2005-07-time frame, insurgents assassinated 1.09 people a day, detonated 18.8 bombs a month, and staged 12.8 arson attacks a month. In 2005, they conducted 43 raids and 45 ambushes. The militants target security forces, government civilians, and the local population. They have killed fellow Muslims and beheaded numerous Buddhist villagers. The insurgents’ actions have crippled the South’s education system, justice system, and commerce, and also have maligned Buddhist-Muslim relations. Overall, the separatists pose a direct threat to Thailand’s south and an indirect threat to the rest of the country. Moreover, their radical Islamic overtones have potential regional and global terrorist implications. The Thai Government spent much of 2004 attempting to ascertain whether the high level of violence was, in fact, an insurgency. To begin with, the government, led by PM Thaksin Shinawatra, was puzzled by the fact that the separatists had not published a manifesto or approached Bangkok with a list of demands. By mid-2004, however, the insurgents had staged a failed, region-wide revolt, and their prolific leaflet and Internet propaganda campaign clearly demonstrated that a rebel movement was afoot. By fall 2005, the separatists had made political demands via the press, all of which centered on secession. By 2006, a coup against PM Thaksin succeeded and the military government that replaced him instituted a new COIN strategy for the south that by 2008 had reduced violence by about 40 percent. Some of the tenets of this new strategy were based on Thailand’s past successful COIN strategies. Whether or not the government has concocted a winning strategy for the future, however, remains to be seen. This paper analyses these COIN campaigns through the COIN Pantheon, a conceptual model the author developed as an analytical tool. It is based on David Kilcullen’s three pillars of COIN.