MEXICO CITY — The Mexican army killed the leader of the Jalisco New Generation Cartel, Nemesio Rubén Oseguera Cervantes, "El Mencho," on Sunday, decapitating what had become Mexico's most powerful drug cartel and thrusting swaths of the nation into chaos. The drug lord was the Mexican government's biggest prize yet to show the Trump administration in its efforts to crack down on the cartels, and his death was met with a forceful reaction from the cartel, known by its Spanish initials CJNG. Cars burned out by cartel members blocked roads in nearly a dozen Mexican states and left smoke billowing into the air. Jalisco's capital, Guadalajara, was turned into a ghost town Sunday night as civilians hunkered down. School was canceled Monday in several states. Oseguera Cervantes was wounded in an operation to capture him Sunday in Tapalpa, Jalisco, about a two-hour drive southwest of Guadalajara and he died while being flown to Mexico City, the Defense Department said in a statement. The state is the base of the cartel known for trafficking huge quantities of fentanyl and other drugs to the