This episode's headline: No Sacred Cows; Political Wrap; Purse Strings - Veto; Nature or Nurture?. The guests include REP. HENRY WAXMAN, [D] California; WARREN RUDMAN, Concord Coalition; MARK SHIELDS, Syndicated Columnist; PAUL GIGOT, Wall Street Journal; CORRESPONDENTS: MARGARET WARNER; KWAME HOLMAN; BOB GARNER. Byline: In New York: ROBERT MAC NEIL; In Washington: JAMES LEHRER