This episode's headline: Abandoning the Motherland; Learning By Choice; Pearl Harbor Remembered. The guests include THOMAS NILES, Assistant Secretary of State; ROMAN SZPORLUK, Professor, Ukrainian History, Harvard University; STEPHEN COHEN, Professor, Political Science, Princeton University; FEDOR BURLATSKY, Former Newspaper Editor; CORRESPONDENTS: ART HACKETT; JIM FISHER. Byline: In New York: ROBERT MacNeil; In Washington: JAMES LEHRER