Rose Kennedy, for one brief shining moment the most powerful mother in America, went over John F. Kennedy's head in 1962 to write directly to Russian leader Nikita Khrushchev. For that, she got a playful scolding from her son. She spunkily wrote a letter asking the Russian leader to autograph pictures of his meeting with her son, and Khrushchev complied. "Would you be sure to let me know in the future any contacts you have with heads of state . . ." John Kennedy wrote to his mother on White House stationery on Nov. 3, 1962, just days after the...