Fifty years ago today, President and Mrs. Kennedy left the White House in the morning for a helicopter ride to Andrews Air Force Base. The president’s 3-year-old son went along and was said to be upset when his father left him to board the flight to San Antonio as the first stop on his two-day political trip to Dallas. Less than 36 hours later, the president’s body returned in a hastily purchased and battered coffin which had to be manhandled out of the hearse, up the stairs and around the tight corner of the rear door of Air Force One.

We know so many details of those hours, but five decades later, we still struggle for a definitive answer as to what really happened. How could a nowhere man like Lee Harvey Oswald kill the shining symbol of American promise? Each anniversary of the assassination, particularly the major ones, are another failure to reach closure. Maybe we don’t want it; there is something maudlin but satisfying about revisiting the gore and grief of the assassination.

From the Zapruder film to Jackie’s blood-soaked gloves and stained pink dress to the little son’s goodbye salute (did he learn that at Andrews?), it is all so vivid and tragic. For many Americans, the Kennedy assassination serves the role tragedy did for the Greeks: A chance, in Aristotle’s belief, to “cleanse the heart through pity and terror . . . to make us aware that there can be nobility in suffering.” Aristotle also said, however, that a tragedy must have a “beginning, middle and end.” The end has been the hard part.