Frida Ghitis: Fentanyl is 50 times more potent than heroin, putting users in mortal peril. She says dealers in the U.S. are spiking other drugs with cheap and accessible fentanyl. The government must act urgently to tighten enforcement, reduce demand and expand access. A decade-long counternarcotics alliance with the U.S. fell apart after President Andrés Manuel López Obrador took office. The chill in relations has left DEA agents scrutinizing press releases to see what types of narcotics Mexico’s military has seized.
