By Daniel Lovering
BOSTON, Sept 22 (Reuters) - Three days after U.S. President John F. Kennedy was assassinated in Dallas in 1963, some 45,000 condolence letters addressed to his young widow, Jacqueline Kennedy, poured into the White House.
That was just the beginning of a flood of correspondence. Over the next two months the number climbed to 800,000, and within two years the first lady had received more than 1.5 million letters from well-wishers of all stripes, united in their grief over her husband's death.
About 250 of the letters were selected by historian Ellen Fitzpatrick and published in a 2010 book, "Letters to Jackie: Condolences from a Grieving Nation."
Now the book has been adapted for the screen in a new documentary, "Letters to Jackie: Remembering President Kennedy", which premiered at the John F. Kennedy Presidential Library and Museum in Boston last week, nearly 50 years after Kennedy was gunned down on Nov. 22, 1963, by Lee Harvey Oswald.
The film, which features archival footage of Kennedy at news conferences, public events and with family, traces the major events of his presidency, from civil rights protests to the Cuban missile crisis.
The 20 condolence letters that shape its narrative, written by ordinary Americans and read by Hollywood actors, give a visceral sense of what the 35th U.S. president meant to many citizens at a time of social and political upheaval.
"I felt as if I was looking at the beating heart of the country," Fitzpatrick said of the letters, which she stumbled across while doing research at the presidential library. "I read more and became all the more convinced that the letters should be brought to light."
A student from New York wrote of her teacher breaking down in tears at the news. A Massachusetts man fondly recalled voting for Kennedy in 1960 and expressed disbelief at the slaying of "a man so much alive" by "a madman with a mail-order rifle."
In another letter, Gabriele Gidion of New York wrote she had fled Nazi Germany, grown up in wartime China, had watched her father die of cancer and seen her roommate in a car accident.
"Yet NEVER, until last Friday, have I felt such a desperate sense of loss and loneliness," she wrote. "President Kennedy was, and always will be, loved by people the world over."
Gretchen Lundstrom, a student at St. Olaf College in Minnesota, wrote: "Our idealism has once again been shattered in the face of human depravity, and it has left an emptiness which will not soon diminish."
Kennedy's assassination in front of cheering crowds while riding in an open motorcade through Dallas was the first of a trio of 1960s political killings in a turbulent decade.
Five years later, the nation looked on in horror again as civil rights leader Martin Luther King, Jr., and later Kennedy's brother and U.S. Senator Robert, were also gunned down.
Another voice in the film was that of Henry Gonzales, a Mexican immigrant who lived in Texas at the time of Kennedy's death and wrote that they were the same age, and like the president, he had served in the South Pacific during World War Two, "but I was no hero.
"We both married in 1953, and my wife is the same age as you are," Gonzales wrote. "We do hope that you will not think all of us Texans bad. There is bad in every sort of people."
Director Bill Couturie recalled being shocked when half the boys in his high school gym class in a conservative part of southern California had cheered at the news of Kennedy's death.
"When those guys cheered, I said, 'You know, I guess I must be a Democrat,'" he recalled at a screening of the film. "It changed my life."
The actors who read the letters in the film include Jessica Chastain, Chris Cooper, Viola Davis, Kirsten Dunst, Anne Hathaway, Laura Linney and Betty White.
Cooper recalled wondering at age 7 if the racist attitudes he encountered in his community were true.
"I came to the conclusion that they weren't, that they were wrong," he said. "Kennedy helped me realize that I was right." (Editing by Scott Malone and Maureen Bavdek)