PUERTO CORTES, Honduras -- The head of a young girl, hacked off with an ax, was found in a burlap bag in October in this industrial port on the Caribbean. The bag also contained a note to President Ricardo Maduro from Mara 18, an ultra-violent street gang, saying that the killing was "in memory" of a gangster who had been killed by police. < SNIP > The gang violence is closely connected to the United States, which spent billions of dollars on Central America's wars during the 1980s. Thousands of Central American refugees fleeing the wars streamed into the United...