If you haven't already, please check out my latest piece with The American Conservative, "What Trump's 'Warning' to Colombia Really Means." It goes into detail about the way in which America's drug war is selectively enforced to advance a Cold War-style agenda.
The Trump administration has criticized Colombia's anti-drug efforts and pressured their country to reinstate its aerial fumigation program. This program was somewhat effective with reducing coca production, but this one method isn't a silver bullet for eliminating the drug supply.
Also, aerial spraying does nothing to combat the demand for cocaine. Hence, cocaine supply always responds to demand and the production is displaced from one region to another. However, you may be wondering why Colombia discontinued this program. The problem is that it also results in widespread collateral damage.
The chemical that is sprayed over the coca fields in Colombia, glyphosate, was banned by the Colombian Supreme Court in 2015 due to research by the World Health Organization, which pointed to a variety of negative environmental and health consequences.
This aerial fumigation program is also unpopular with Colombia's farming sector because the spraying is indiscriminate and the chemicals kill all plants in the area, not just coca. In fact, the government of Colombia reached a $15 million settlement in a lawsuit with its southern neighbor, Ecuador, due to the damage from aerial spraying that drifted over the border.
Despite these facts, Secretary of State, Rex Tillerson, and the Trump administration have continued to bang the drum calling for the Colombian government to restore this program. Keep in mind, aerial spraying conveniently benefits a couple of politically-connected corporations.
For fifteen years, the U.S. government contracted with the private defense company DynCorp to spray glyphosate, which is developed and patented by Monsanto, over the coca fields in Colombia. (Glyphosate is the key chemical in their weed-killer, RoundUp.)
That brings up another interesting topic. The Trump administration is indirectly promoting Monsanto's interests at a time when other government entities are confronting the company's tactics. Case in point, Monsanto's officials and lobbyists were recently banned from the European parliament. Coincidentally, this decision came about after Monsanto's representatives declined to attend a meeting about allegations that their company manipulated safety studies related to glyphosate. (The New York Times also published an excellent article recently about the company's woes in the U.S.)