The principles of State responsibility set out in Chapter 4 confirm that States bear some responsibility for preventing the occurrence of internationally wrongful acts. The standard implied in this obligation is one of due diligence: The State is required to take “all reasonable and necessary measures to prevent a given event from occurring.” A decision on what is “reasonable or appropriate” in a particular situation will require consideration of the facts of the case and surrounding circumstances, including the capacities of the State, as well as the relevant primary rules.

In the context of trafficking in persons, prevention refers to positive measures to stop future acts of trafficking from occurring. Policies and activities identified as “prevention” are generally those considered to be addressing the causes of trafficking. While there is not yet universal agreement on the complex matter of causes of trafficking, the most commonly cited causative factors are those that: (1) increase vulnerability of victims and potential victims; (2) create or sustain demand for the goods and services produced by trafficked labor; and (3) create or sustain an environment within which traffickers and their accomplices can operate with impunity. From this perspective, prevention can be seen to include a wide range of measures – from providing women with fair and equal migration opportunities, to strengthening the criminal justice response in order to end impunity and deter future trafficking-related crimes.