Several Latin American governments have been challenging various approaches to the war on drugs, traditionally pushed by the United States. Countries like Colombia, Chile and Bolivia are "just saying no" to -- or at least severely modifying -- long held U.S. anti-drug strategies employed in the region like prohibition, the eradication of narcotics-producing crops and presenting a unified militarized front against growers.

The rise of disagreements on drug policy in the region is a sign of the strain the decades-long war on drugs has put on U.S. relationships with Latin American countries. As Paul Gootenberg, a historian who specializes in Latin America, told the New York Times, “For the first time in 40 years, there is significant pushback from Latin American countries, which endured much of the drug war’s suffering.”

On Thursday, Colombia blocked the aerial spraying of coca plants, whose leaves are used to used to produce cocaine. Though, in balance with that measure, Colombia has actively begun looking for other solutions for hampering coca plant operations, including manual destruction of the crops or releasing coca-eating butterflies on growing operations.

Colombia's decision to stop the U.S.-backed aerial spraying came after the World Health Organization declared in March that glyphosate, a chemical herbicide used in the procedure, was a carcinogen.

Bruce M. Bagley, a specialist on the Latin American drug trade at the University of Miami, told the New York Times, “The cost in blood and treasure from the drug war has been overwhelming,” adding that “leaders are looking at the militarized approach and saying they don’t want 40 more years of Colombian-like policies.”

Years ago the neighboring nation of Bolivia ousted the United States Drug Enforcement Administration and now lets farmers grow small amounts of the coca, which has been grown in parts of the Bolivian Andes since the Inca era. And Chile is currently gathering its first harvest of medical marijuana.

The resistance to what are being perceived as failed anti-drug strategies in Latin America is a sure sign that the U.S. influence regarding drug policy in the region is waning.

Yesid Reyes, the justice minister in Colombia, recently described his country’s disillusionment with decades of U.S. drug policy in the region this way:

“If you use the same tools for 50 years and the problem isn’t solved, something is not working right.”