“You know, of course, that your grandfather had once been a very pious, religious man?”

I am having dinner with my aunt – my late mother’s last surviving sister. We are discussing her father/my grandfather, a man who died exactly 40 years ago, a man who has always been a mystery to me.

My aunt’s assessment of my grandfather’s religiosity struck me as wrong. I had always heard that he was anti-religious, that he was an atheist, that he was a Communist. My grandfather hated religion so much that his final words to my mother, uttered months before I entered rabbinical school, were simple and blunt: “Can’t you talk him out of this madness?”

I could not let this revelation simply sit there. I prodded my aunt to tell me more.

“Your grandfather used to go to shul all the time. I distinctly remember it, from when I was a little girl. And then, one day, he took his tallit, and his prayer book, and he threw them both on the floor, and he yelled: ‘That’s it. I am through with this!’”

“How old were you when this happened?” I asked.

My aunt thought for a few moments. “I must have been 10-years-old.”

Temporarily forgetting that old taboo about asking a woman’s age, I asked her: “Remind me: in what year were you born?”

To which she responded: “1928.”

I performed a very rapid mathematical calculation in my head. “So, this would have happened in 1938, right?”

“I guess so…”

This is what my aunt had forgotten, or perhaps, had never known. It was a story that my late mother had told me, years ago, when I was a young boy.

My grandfather had a young relative, somewhere in Czechoslovakia. Her parents could see the gathering storm clouds on the Jewish horizon, and they wrote to my grandfather. “Our lives have been rich and full,” they wrote. “But, our daughter has not yet begun to live. Will you adopt her as a foster child, and bring her to the United States, and raise her?”

My grandfather sprang into action. He traversed the jungles of red tape, and finally, he was able to secure the proper papers for this young girl, that would allow her to come to the United States.

According to my mother, the day after my grandfather had completed his work, the Roosevelt government shut its doors, and decided to allow no more refugees to enter this country. The girl and her parents were lost.

For decades, I have been trying to imagine her name, thinking of every variation of my grandfather’s last name, surmising that she had been deported to Theresienstadt. Perhaps she had died there, or in Auschwitz or Treblinka.

When my grandfather had learned of his failure to rescue his young relative — which was really the Roosevelt government’s moral failure — he lost his faith.

He should have lost his faith in Franklin Roosevelt, who was virtually godlike to that generation of American Jews. And yes, perhaps he did lose his faith in Roosevelt — but it manifested itself as a loss of faith in God, and in Judaism — and in wanting to have anything to do with the Jewish people.

It is now 78 years later, and I am my grandfather’s heir. I am the only one left who can tell this story.

True — my aunt had known something about my grandfather and his fatal failure with government bureaucracy.

But she had never connected the dots of the calendar, had never figured out that the mysterious loss of my grandfather’s faith was linked to his loss of faith in the American system.

It occurs to me: I am the only person who says kaddish for my maternal grandparents during Yizkor on Yom Kippur.

But this year, I shall be saying kaddish not only for my grandfather. I will be saying kaddish for his faith. I will be imagining his anger, his bitterness, his crippling disappointment.

I will be praying that I will not have to say kaddish for that corner of the American dream and the American story — that corner that affirms our story as a land of exiles, immigrants, refugees.

And, yes — I will say kaddish — as I have done so for years — for that nameless child, wondering about the woman she would have grown up to be, living in my grandparents’ house in Queens, growing up with my mother and her sisters — the woman who would have come to seder every year and would have told us, with that delightful accent, about her life and about how a sweet grocer had redeemed her.

Jeffrey K. Salkin is the senior rabbi of Temple Solel, in Hollywood, Florida, and a frequent writer on Jewish and cultural matters. His blog is called Martini Judaism: for those who want to be shaken and stirred.