This episode's headline: Shields and York; Senegal's Success; Founding Fathers; Conversation. ANCHOR: JIM LEHRER; GUESTS: MARK SHIELDS; BYRON YORK; JOYCE APPLEBY; RICHARD BROOKHISER; WALTER ISAACSON; JOSEPH ELLIS; ANNE TAYLOR FLEMING; CORRESPONDENTS: KWAME HOLMAN; RAY SUAREZ; SPENCER MICHELS; MARGARET WARNER; GWEN IFILL; TERENCE SMITH; KWAME HOLMAN