1940s: Mexico was the top producer of opiates during WW1 and WW2. After those conflicts ended, the opium planters turned to illegal trade.
The opium poppy plant, the plant from which opium and related opiate drugs are produced, is not endemic to the Americas.
1882: The US Chinese exclusion act caused the expulsion of many Chinese, among them, opium poppy planters. Many of them relocated to to Mexico where they started planting opium again.
1860s: The Chinese immigrants involved in opium trade had opium dens in San Francisco and other places. They became addicted during an opium epidemic in China.
1839: The Chinese as a nation were against opium use, but the British forced them to legalize opium. All that is known as the Opium wars, which was the British weaponization of opium to extract wealth from China to make up for the lost money in the Americas.
1776: The British lost the American revolutionary war and started to accumulate a trade deficit with other countries, notably China.
Conclusion: The East India Company was the first modern narco organization, Lord Palmerston is personally responsible for centuries of drug related violence. The guy was an educated person (in fact, 2x Prime Minister) and knew what he was doing all along.
This comment will make everyone angry but it is the truth.