Frey teaches at New Lebanon School, one of the town’s three Title I elementary schools. Some know Greenwich as a tony New York suburb. But one corner of it is not. In her class of 18, there are 14 Latinos, two African Americans and two whites. Seventeen are either immigrants or the children of immigrants.

Frey was sick that day, so I was recruited to read to her students. The children, 9 and 10, gathered in front of me on the rug. They had barely heard of Nazi Germany or the war, and couldn’t say when the events in question took place. But they did have a firm sense of right and wrong. They blanched when I told them what the Nazis had done and how they had discriminated.

I opened the book and began to read, pausing after each page to show the children the illustrations that help illuminate the story. Deedy’s picture book is myth inspired by fact. In her telling, the king encouraged all his people to wear on their outer clothing the yellow star meant by the Nazis to identify and isolate Jews, so the invaders wouldn’t know who was Jewish and who was not. History teaches that the king protected Denmark’s Jews by other means. But the students got the point: Jews, non-Jews, all were Danes.

Since President Donald Trump issued his initial immigration executive order, temporarily barring U.S. entry to visa holders from seven predominantly Muslim nations, and banning refugees from all nations and those from Syria indefinitely, I’ve thought quite a bit about Deedy’s book, and why Frey chose it for her students. I sought her out in her classroom.

Frey has taught for 30 years, the last four at New Lebanon. She invited me to sit at a round, child-size worktable near the center of the room. We were alone; her students were in gym class. The wall in front of us was lined with baskets of books that made up the room’s library. Above them was a partial timeline of U.S. history, from the first British expedition to Roanoke Island, N.C., in 1584, to the civil-rights era, in 1960.

Frey said that the class had just begun a unit on historical fiction — a genre with which few of the students were familiar. She had selected “The Yellow Star” for its simple theme and its schoolchild accessibility. “This is the first time that most of them have been exposed to historical time periods,” she said. “At this age, they know famous people, but they don’t have a sense of what happened. They know Martin Luther King, and when I returned the day after his holiday, we talked about how a person’s actions and words can cause change. They made the connection between Dr. King and King Christian.”

Change and action and the power of words have taken on particular meaning for her students.

“The day after the [presidential] election, several children told me they were very worried about what might happen to them,” Frey said. “They talked about it that morning among themselves when they came into class. They were worried about their families. One boy came to me in tears and said he was leaving the country, that his family was going back to Portugal. He went around the room, saying goodbye to his friends. Later that day I called his dad. The boy was mistaken; the family was staying.”

But the damage was done.

It took 15 minutes to read “The Yellow Star” to the class. Upon finishing, I looked up at the students. From their expressions, I feared I had upset some of them all over again. When I asked their thoughts on those who had threatened Denmark’s Jews, their response was heartfelt, uncomplicated. “That’s wrong,” blurted one boy, to general agreement. “It’s not fair,” seconded another.