We call that Salvation Jane in my state. We are so dry here that other people's curses are our salvation....or that of our sheep when drought stricken.
Maybe the Kennedys just found salvation more quickly than others?
But, to be serious for a moment, in Jack Kennedy's generation you could almost have justified talk of a curse.
Joe Jr killed in the war in a plane crash, Kathleen killed in a plane crash, Rosemary born with a disability and lobotomized into idiocy, Jack and Bobby assassinated.