The story seems to unfold in slow motion as the painstaking exchange of letters journey across continents and from state to state, their information often outdated by the time they arrive. Each page adds a layer of sorrow as the tortuous process for gaining entry to the United States — involving sponsors, large sums of money, affidavits and proof of how their entry would benefit America — is laid out. The moment the Franks and their American supporters overcame one administrative or logistical obstacle, another arose.

Even the assistant secretary of state at the time, Adolf A. Berle Jr., despaired of the bewildering maze of regulations. As Richard Breitman, a historian at American University, pointed out in a separate background paper, Berle wrote in January 1941 that some consulates ask for a trust fund. “Others ask for affidavits. One particularly shocking case stated that nothing would be accepted save from a relative in the United States under a legal obligation to support the applicant,” he said. “It does seem to me that this Department could pull itself together sufficiently to get out a general instruction which would be complete enough and simple enough so that the procedure could be standardized.”

Ultimately, powerful connections and money were not enough to enable the Franks, not to mention most other European Jews, to break through the State Department’s tightening restrictions. By the summer of 1942, the Franks were forced into hiding. They remained in the secret annex for two years before being turned in, probably by the same courier who initially may have tried to blackmail them. As schoolchildren around the world know, the story ends with the death in concentration camps of 15-year-old Anne, her sister Margot and her mother, Edith, and the publication of Anne’s diary, now a literary and historical landmark that personalizes the Holocaust’s immeasurable loss.

Image Letters chronicling Otto Franks thwarted efforts to get his family out of the Netherlands are at the YIVO Institute in Manhattan. Credit... Hiroko Masuike for The New York Times

Mr. Breitman explained that after France fell to the Germans in June 1940, fears grew in the United States of a potential fifth column of spies and saboteurs peopled by European refugees. By June of 1941, no one with close relatives still in Germany was allowed into the United States because of suspicions that the Nazis could use them to blackmail refugees into clandestine cooperation. This development closed off the possibility of getting the Frank girls out through a children’s rescue agency or having Otto Frank depart first in the hopes that the rest of his family would quickly follow.