This episode's headline: Safe and Secret?; Invisible Issue; On the Stump. The guests include SEN. JOHN GLENN, [D] Ohio; TROY WADE, Energy Department; RICHARD STAROSTECKI, Energy Department; GOV. MICHAEL DUKAKIS, Dem. Presidential Candidate; VICE PRESIDENT GEORGE BUSH, GOP Presidential Candidate; CORRESPONDENT: SPENCER MICHELS. Byline: In Washington: JAMES LEHRER; In New York: CHARLAYNE HUNTER- GAULT