"Although US assistance is provided for counter-narcotics purposes only, there is a clear linkage between the Colombian government's counter-narcotics and counter-insurgency strategies. the Colombian government believes that, by striking at the drug trade, it also strikes at the economic center of gravity of the guerrillas. That is, by destroying the coca and poppy fields, drug-production facilities, and transportation networks, the government can also degrade the guerrillas' ability to carry on the war.
"Whether this is an accurate assessment remains to be seen."

Source

Rabasa, Angel & Peter Chalk, "Colombian Labyrinth: The Synergy of Drugs and Insurgency and Its Implications for Regional Instability" (Santa Monica, CA: RAND Corporation, 2001), p. 65.
https://www.rand.org/pubs/mon…
http://m.rand.org/content/dam…