I have been thinking a lot about a 16-year-old girl whose name I don’t know. As of early last week, she was being held in a detention facility in Texas along with other children who were picked up for unauthorized crossing of the U.S. border, often with their families.

This teenager, according to the Associated Press, took it upon herself to care for a toddler who had been separated from her aunt, and also was teaching other children in the cage they all shared to change her diaper.

When I have felt helpless and hopeless recently over the cruel acts my country is committing on behalf of me and my fellow Americans, I have offered up thanks to her. She showed humanity when none was shown to her, and she carried out an act of deep compassion that Americans safe in their homes are unable to perform.

I think one of the reasons that the Trump policy to separate children from their parents at the border sparked such deep outrage is that it doesn’t take a moment of imagination for a parent to understand how traumatizing the experience would be.

My 2-year-old son, who lives a secure, safe and privileged life, recently has started clinging to me and crying when I leave him at daycare.

Even though I know he is being cared for by sweet women who are familiar to him and who love him, that he will be read to, sung to, fed when he is hungry and held when he cries, and that I will receive photos of him smiling and playing via text messages throughout the day, it’s still hard for me to leave him when he’s crying, “I want my mommy!” But I’m able to do it because I know that his tears are brief, and behind them even he knows that I will be back before long and that he is safe. And most importantly, I’m leaving him in a place and with people that I chose for him.

Caring for children is the hardest thing in the world, but it’s also simple.

To be happy and healthy and learning and growing, kids need love, stability, regular routines, reliable care from and attachment to their parent. When families have their basic needs met, it’s not hard to provide this environment of safety and nurturing to children.

But when families have their worlds torn apart by war, violence and poverty, this stabile environment breaks down. And when parents flee with their children as refugees, children cling to their parents as their only remaining remnant of stability.

That’s why every parent who’s ever comforted a child can instantly understand the immediate damage that would be done to a child wrenched from their arms and placed into an alien environment.

The president of the American Academy of Pediatrics, Dr. Colleen Kraft, called it child abuse after visiting shelter for immigrant children. There she saw a 2-year-old girl crying inconsolably. A shelter worker ineffectually offered the child toys; she wasn’t allowed to touch her or pick her up, she said.

Being separated from a trusted caretaker with no reassurance of when they will be reunited causes trauma to children’s brains that can seriously affect their future health and development, Kraft said.

All I could think when I read this was that I wouldn’t want my son to spend even an afternoon in a place where no one would hold him when he cried. It’s inhumane.

As I write this, President Trump has announced a reversal of the family separation policy. Under an executive order, families who are picked up for crossing the border without authorization will be kept together, and Border Patrol will not refer the parents for prosecution going forward.

Even if these changes are carried out, this country is still failing mightily at being a place of refuge for people who are desperately fleeing dangerous conditions in their home countries. And there is no plan in place to reunite the thousands of children who have already been separated from their parents.

I hope what all Americans will remember from this deplorable episode that we are being led by people who are so cruel that they thought nothing of tearing children from their families and holding them captive, and that they defended the practice to the ground until the public condemnation grew overwhelming.

In the absence of leadership, I’ll remember the compassionate example set by a teenage girl whom I very much hope is OK.