This episode's headline: Curing Medicare?; The Money Chase; Changing Times; Summer Daze. ANCHOR: JIM LEHRER; GUESTS: SEN. JOHN BREAUX, [D] Louisiana; MARTIN CORRY, American Association of Retired Persons; JAMES BAKER, Former Secretary of State; ENRIQUE KRAUZE, Author; JORGE DOMINGUEZ, Harvard University; JAMES JONES, Former U.S. Ambassador to Mexico; CORRESPONDENTS: CHARLES KRAUSE; MARGARET WARNER; ANNE TAYLOR FLEMING;