This episode's headline: Lithuania - Forcing the Issue; Zimbabwe Election; Water on the Brain; Conversation. The guests include SEN. BILL ARMSTRONG, [R] Colorado; SEN. JOSEPH BIDEN, [D] Delaware; VICTOR NAKAS, Lithuanian Information Center; OLEG DERKOVSKY, Soviet Embassy; ROBERT STUTMAN, Former Drug Enforcement Agent; CORRESPONDENT: MIKE HANNAH; ESSAYIST: JIM FISHER. Byline: In Washington: JAMES LEHRER; In New York: CHARLAYNE HUNTER- GAULT