Federal officials were caught off guard when the Trump administration announced its “zero tolerance” immigration policy on migrants crossing the southwest border. The policy to criminally prosecute anyone who crossed the border illegally, announced by Attorney General Jeff Sessions in April, was reversed months later by President Trump, but only after it caused a public outcry due to the separation of parents and children.The policy was fully instated in May, but because they did not know in advance about the policy, officials at the two agencies tasked with processing the migrant families were not prepared to enforce it.