Leafing through A Book of Ages, you begin to realize how many lives were changed by the events of that one day. Courses changed, careers delayed or created, stories rewritten.
Churchill gained an ally and Hitler an enemy. The war in Europe had transformed Churchill from a back number into the indispensable leader, and December 7th made it likelier he would prevail, because FDR suddenly had the ability to act. FDR became a war president. Douglas MacArthur, George Patton and Dwight Eisenhower had a reason to put their boots on. (MacArthur's most recent engagement had been against World War I veterans camped on the Capitol Mall.)
Men at arms were relevant, and thousands of people who never thought of themselves as military men (or women) were put into uniform. Norman Mailer and Gore Vidal and Kurt Vonnegut would write war novels out of the experience. J. D. Salinger's story about a prep school boy named Holden Caulfield was slated to appear in the New Yorker that December. After Pearl Harbor was attacked the editors set it aside for the duration; it suddenly seemed frivolous. Salinger would see action on D-Day and meet Hemingway in Paris, and fight in the Battle of the Bulge. The war would send echoes down through his subsequent work, in characters' disrupted lives and sudden suicides in postwar living rooms.
Hemingway had seen World War I as a teenager; now he was too old to fight, but he outfitted his fishing boat to hunt submarines. In 1944 he single-handedly liberated the Ritz Bar in Paris. Edward R. Murrow became "Edward R. Murrow" reporting on a war that America was half interested in. That too changed. Walter Cronkite cut his journalistic teeth as a war correspondent, and Martha Gellhorn outran most of her male counterparts to get the big story. Her professional rivalry with Hemingway ended their marriage.
Richard Nixon's war was spent playing cards in the Pacific; he won enough from poker to win a seat in Congress. James Michener would write stories about his own experiences in the Pacific, and Rodgers and Hammerstein would make a musical from them. James Stewart enlisted and rose through the ranks to become a bomber pilot over Germany. John Wayne, a near contemporary, made the decision to stay home and play war heroes in movies. Bandleader Glenn Miller lost his life over the English Channel. On FDR's death Harry Truman was transformed from an obscure figure to the most powerful man in the world, burdened with the decision to deploy the atomic bomb. J. Robert Oppenheimer, who marshaled the hundreds of scientists to create that weapon, was dismayed by what he had created. Charles Schulz discovered first-hand how inhuman humanity could be; he would express this cynicism in a comic strip.
The most galvanizing event in American life in the 20th century was triggered by the events of this day 68 years ago on an obscure island in the Pacific. Nobody's life would be the same again.