MIAMI — When the cargo ship “Miss Lilie” left Miami one recent afternoon and pulled into port along Haiti’s northwest coast, it had all the markings of a legitimate government operation. Men in canoes waited until nighttime to unload the freight and stash it on anearby island. Armed anti-drug trafficking officers showed up at the wharf and claimed they were sent to take the cargo, while vehicles with official state and police plates waited to transport the load along a perilous, gang-controlled road. But the cargo was far from legal. It contained 120,000 high-power rounds — a deadly cache outl...