Since 1899, Colombia has been embroiled in a long and bloody series of interconnected insurgencies. The most famous of these are the Colombian fight against the Fuerzas Armadas Revolucionarias de Colombia-Ejército del Pueblo (FARC) and the Ejército de Liberación Nacional (ELN). The campaigns against these violent non-state armed actors, as well as against the other groups analyzed in this study, show the true nature of unconventional warfare and counterinsurgency. These campaigns are not quick, they are not clean, nor are they easy. To the contrary, these campaigns are the most difficult and complex a nation can face, requiring the delicate and effective application of all elements of national power through a synchronized and flexible campaign plan with clearly defined end states. Most importantly, the nation waging these campaigns must take ownership of the problem in order to effectively address it. Colombia stands as a premier case study in this regard. Assessing both the successes and failures of the Colombian efforts to stabilize their country provide an invaluable resource for US Special Operations Forces to professionally develop in their craft. This study, along with the other ARIS works, provides a vital historical prospective for all SOF personnel to read, learn, and internalize. It is this knowledge of how governments have successfully or unsuccessfully met these challenges and how the insurgents and revolutionaries fighting them did the same that will allow us to evolve and meet the challenges of the future operating environment. BG Kurt L. Sonntag Commander Special Operations Command South