In Lutz and Lotspeich, Prot Proj J Hum Rights Civ Soc 2:124–199, 2009, , causal linkages between commercial sex and human trafficking were examined. It was determined that a three-link chain of necessary conditions existed: a population vulnerable to trafficking, a capable trafficking organization, and a sex market, was identified. All three links are required for trafficking into commercial sex. Thus, trafficking can be examined by policy intervention at any link. Prospects for policy success at the three points of intervention were compared. It was shown in Lutz and Lotspeich, Prot Proj J Hum Rights Civ Soc 2:124–199, 2009,  that a strategy of suppressing sex markets is least likely to be successful in reducing human trafficking.