Maybe the article will help to explain the puzzle:
Washington Post gift link
Fentanyl seizures are plummeting.
The phenomenon has received little notice in Washington, where the Trump administration has made fentanyl-trafficking cartels a national-security priority. “Narcotics of all kinds are pouring across our borders,” said a White House statement in March, announcing stiff tariffs on Mexico and Canada.
New data suggest a more complex story. The U.S. government’s average monthly seizures of fentanyl at the Mexican border have dropped by more than half — from 1,700 pounds in 2024, to 746 pounds this year, according to Customs and Border Protection data. The White House says the drop is “thanks to President Trump’s policies empowering law enforcement officials to dismantle drug trafficking networks.” Yet the decline started before Trump took office in January. (While officials only manage to detect part of the fentanyl crossing the border, the figure serves as a proxy for supply).
The contraction represents something of a mystery, say antidrug agents and researchers. Are Mexican cartels producing less fentanyl? Or have they simply found new ways to sneak it across the border? Fentanyl is still cheap and widely available in the United States, according to analysts and drug enforcement agents. Yet overdose deaths plunged nearly 27 percent last year, compared with 2023, according to estimates published by the Centers for Disease Control and Prevention. The biggest cause of such deaths are illicit synthetic opioids, especially fentanyl.