Recent attacks on villages in Mexico’s western state of Michoacán reveal the cartels’ growing paramilitary-style power, using drones, I.E.D.s and other weapons of war. Paulina Villegas examines the aftermath of these assaults.

Under pressure from the government and each other, some of Mexico’s most powerful criminal groups are amassing homemade mortars, land mines, rocket-propelled grenades and bomber drones.