According to the FBI, 33,000 violent street gangs, motorcycle gangs, and prison gangs, with nearly 1.4 million members, are criminally active in the U.S. today. One of the most notorious and dangerous gangs, Mara Salvatrucha, or MS-13, originated in Los Angeles and has as many as 50,000 members. The Justice Department credits gangs with illegal smuggling, transportation, and distribution of large amounts of drugs in the United States. This expansive...