Sadly, having been there for the historic moments of JFK's brief presidency, the Irish Mafia was also there when it ended. Powers was actually in the car behind Kennedy when he was assassinated in Dallas on November 22, 1963. Powers even helped remove Kennedy's body from the car. One observer, in Maier's book, noted that the diverse cultural groups in Kennedy's inner circle reacted to his death in different ways. "The Irish were having a wake, the Protestants were at a funeral, and the Jews were weeping and carrying on."
Perhaps it's not surprising that as conspiracies have come to surround JFK's death, the Irish Americans are said to have played a role in that, too. After Kennedy was declared dead, doctors reportedly wanted to perform an autopsy in Texas. It has been said, however, that O'Donnell forcefully persuaded doctors to allow the autopsy to instead take place in Washington, raising questions about the accuracy of the procedure.
Either way, O'Donnell took the death of Jack - and, in 1968, Bobby - very hard. He fell under the sway of alcohol and was just 54 when he died in 1977. His daughter Helen O'Donnell later wrote a book entitled "A Common Good: The Friendship of Robert F. Kennedy and Kenneth P. O'Donnell."
Powers, meanwhile, became a driving force behind the JFK Library and Museum in Boston. He served as curator when it opened in 1979, and retired in 1994, before dying at the age of 85 in 1998. Finally, O'Brien became chairman of the Democratic National Committee in 1968, and later was targeted for investigation by Richard Nixon. O'Brien later left politics and became commissioner of the National Basketball Association, before dying in 1990 at the age of 73. "The Irish," JFK once said to O'Donnell, "do seem to have an art for government." The president then paused, considered his company, and added: "Perhaps we are both prejudiced."