-- It was a brazen assault, not just because it targeted the city's police station, but for the choice of weapon: grenades. The Feb. 21 attack on police headquarters in coastal Zihuatanejo, which injured four people, fit a disturbing trend of Mexico's drug wars. Traffickers have escalated their arms race, acquiring military-grade weapons, including hand grenades, grenade launchers, armor-piercing munitions and antitank rockets with firepower far beyond the assault rifles and pistols that have dominated their arsenals. Most of these weapons are being smuggled from Central American countries or by sea, eluding U.S. and Mexican monitors who are focused on...
