From the epilogue: this book "is about the treatment of children--the country's own young citizens--as foreign and less American than actual foreign children. It is about a nation that has historically been capable of seeing some children as enemies of the American promise because the promise historically had not been made to them."
Basically, the children of Nazis brought to El Paso by Operation Paperclip were firmly embraced and given every opportunity to succeed by the Anglos in charge, while the "Mexican" children (Latine citizens) were short-changed at every turn, their systemic disadvantages treated as individual failures and their failure to thrive chalked up to racial inadequacies. Anglo Americans could see the Nazis' children as fellow white people with a common cultural heritage of domination, whereas they could not see the Mexican children as belonging to their cohort.
I would've been much angrier at the revelations of this book if I hadn't grown up in the rural counterpart to El Paso, where power dynamics between the Anglo minority and the Mexican-American majority were much the same. Even during my childhood, the 80s, students were threatened with paddling if they were heard speaking Spanish in the classroom--and this was in a school with a Latino principal and mostly Latine teachers. So the racist mindset, supposedly an apolitical ambition to achieve the best for the child, was well internalized.
This is a scrupulously researched book that takes care not to stray too far from its subject when drawing conclusions, but I wanted more. For example, I would be interested to see how the Paperclip children's experience in Huntsville, Alabama, compared to their time in El Paso. But I may only be dissatisfied because, as I wrote above, I was already prepared for the discoveries Perrillo describes.