This episode's headline: Looking Further; The Johnson Tapes; As We See It; Prize Theory. ANCHOR: JIM LEHRER; GUESTS: ROBERT SURO, Washington Post; MICHAEL BESCHLOSS, Presidential Historian; THEORY:MYRON SCHOLES, Nobel Laureate, Economics; ROBERT MERTON, Nobel Laureate, Economics; ANDREW KOHUT, Pew Research Center; DAVID FISCHER, World Affairs Council of Northern California; JIM KOLLAER, Greater Houston Partnershi; ROBERT PINSKY, Poet Laureate; CORRESPONDENTS: PHIL PONCE; PAUL SOLMAN; ELIZABETH FARNSWORTH;