"Operation Pied Piper," as it was called, proved deeply traumatic for the children who were separated from their parents. "London children," said Anna Freud, "were on the whole much less upset by bombing than by evacuation to the country as a protection against it."The parents were likewise traumatized. British psychologist John Bowlby, the father of Attachment Theory, went on to study these families and to propose that disrupted attachment caused the children permanent emotional scarring that could manifest in an inability to trust anyone, difficulty maintaining positive relationships, and a sense of an unreliable world. Those deficits in turn led to unreliable behavior and even an increased tendency toward criminality.For decades, the wisdom had been to place sick children in a sterile environment, isolated from the risk of infection — but also from their parents. But research finally showed that the danger of losing parents was far worse than the danger of imperfect sterility. Children did not thrive when they were fed and clothed but not interacted with; in fact, such children died at alarming rates, while those exposed to germ-laden affection were more likely to thrive.The lesson needs to be remembered today, in the United States: Separating children from their families can destroy them.It is human, loving responses, emotional mirroring and attention, that allow the brains of children to develop positively. Such love is usually in short supply for children removed from their families. More recent evidence of the dangers of social neglect are reflected in the high incidence of reactive attachment disorder among children from Romanian orphanages, many of whom have proved beyond healing even when adopted by loving parents. Abuse and neglect and separation from primary attachment figures all cause irreversible psychic decay.Recently, such enforced separations of migrant children from the parents at the southern border, became US government policy. Mothers and fathers were detained for deportation and their children were taken away, with slim to no chance of reuniting soon, and neither side of the family unit knowing where the other is. Such a policy destroys the most basic element of the parent-child relationship, which is the child's belief that the parent can keep him or her safe, and that the parent is powerful and reliable.The separation of immigrant families from their children is not merely a disgusting failure of sympathy by the American government, but also a surefire way to break thousands of children.One of the great advances of the 20th century was the understanding of parent-child attachment and the emergence of a society that prioritizes parental care; one of the worst developments of the 21st is this sudden disavowal of those principles. The British psychoanalyst D.W. Winnicott famously said, "There is no such thing as an infant. There is only an infant and his mother. … Without maternal care, one would find no infant." The principle extends through much of early childhood, and in modified form, through adolescence.Children need protection and security if they are to develop into functional adults. Of the "under 3,000" (according to Health and Human Services Secretary Alex Azar) children separated from their families by immigration authorities in recent months, at least 100 are younger than five. Every day that they are kept apart from their parents is another day of damage.Despite the bluster of the administration and claims that the policy is being reversed, only 522 of these families have been reunited as of this writing, according to the Department of Homeland Security, which provided that figure in late June. It has declined to offer further information about reunions since then. The children are held by the Department of Health and Human Services; the adults, by the Department of Homeland Security. Healing the separations therefore requires the cooperation of two different sections of the government.I recently released a film based on my book, "Far from the Tree." It's a study of how the love of good parents allows people with differences and disabilities to thrive, and serves as an impassioned plea for those whom society would marginalize: people with Down syndrome, with dwarfism, with autism, with criminality; and people who are gay. It does not look at separation, but serves as a celebration of unity, documenting the strength of parental commitment in shaping identities. It responds to the crisis in empathy that affects our interactions with disadvantaged people. It is about finding the humanity within families dealing with marginal conditions.The film was not made to be released at a time of atrocities such as these now unfolding in US immigration policy, but it comes at a time when the universal value of the protection of children is thrown into question by these forced separations. The film is about extreme love; the immigration crisis is about the devaluation of love.