This episode's headline: Making His Case;'92 - Voice of the People; The Impact; Gang Glamour; Ohio - Battleground State. The guests include PRES. BUSH; GOV. CLINTON; DAVID GERGEN, U.S. News & World Report; MARK SHIELDS, Syndicated Columnist; CHAVEZ, Political Analyst; CORRESPONDENTS: CHARLAYNE HUNTER-GAULT; ELIZABETH BRACKETT; CLARENCE PAGE. Byline: In New York: ROBERT MacNeil; In Washington: JAMES LEHRER