This episode's headline: Terrorist Act; Destination Mars; Power Politics; World of the Rings; Communal Voices. ANCHOR: JIM LEHRER; GUESTS: STEPHEN COHEN; HUSAIN HAQQANI; JOHN YOO; PAM KARLAN; MICHAEL DIRDA; CORRESPONDENTS: KWAME HOLMAN; RAY SUAREZ; SPENCER MICHELS; MARGARET WARNER; GWEN IFILL; TERENCE SMITH; KWAME HOLMAN