March 3rd, 2018 
(USA TODAY) — CHIHUAHUA, Mexico — As more U.S. states legalize the use of marijuana, Mexico’s violent drug cartels are turning to the basic law of supply and demand.
That means small farmers, or campesinos, in this border state’s rugged Sierra Madre who long planted marijuana to be smuggled into the United States are switching to opium poppies, which bring a higher price. The opium gum harvested is processed into heroin to feed the ravaging U.S. opioid crisis.
“Marijuana isn’t as valuable, so they switched to a more profitable product,” said Javier Ávila, a Jesuit priest in this region rife with drug cartel activities.
Laws allowing marijuana in states like Colorado, Washington and California are causing shifts in the Mexican underworld that have also led to increased violence as the cartels move away from its cash cow of marijuana to traffic more heroin and methamphetamines.
U.S. Customs and Border Protection statistics show that marijuana seizures fell by more than half since 2012, while heroin and methamphetamine seizures have held steady or markedly increased.