As protestors and police officers clash on the streets of divided cities such as Baltimore, Maryland, and Ferguson, Missouri, some police departments are stockpiling a highly controversial weapon to control civil unrest. It’s called Skunk, a type of “malodorant,” or in plainer language, a foul-smelling liquid. Technically nontoxic but incredibly disgusting, it has been described as a cross between “dead animal and human excrement.” Untreated, the smell lingers for weeks. The Israeli Defense Forces developed Skunk in 2008 as a crowd-control weapon for use against Palestinians. Now Mistral, a company out of Bethesda, Maryland, is providing it to police departments...