Jeff Greenfield explores three moments in U.S. history; the near assassination of President-Elect Kennedy by a 73-year-old suicide bomber in December 1960, the assassination of Robert Kennedy on June 5, 1968, and the presidential debate between Gerald Ford and Jimmy Carter in October 1976. Instead of recounting the historical record, Mr. Greenfield opines on what might have happened had the participants made different choices, which would have altered the events of the day. Jeff Greenfield presented his thoughts at Politics and Prose Bookstore in Washington, D.C., on March 11, 2011