Appointment as ambassador by LBJ; Guam Conference, 1967; impressions of Nguyen Van Thieu and Nguyen Cao Ky; Vietnam's presidential election campaign in 1967; religious factions; advice to Thieu; recommendation for U.S. to close Viet Cong's use of Cambodia and Laos as sanctuaries; lack of communication between South and North Vietnam; objectives of the pacification program and its implementation; agricultural gains in South Vietnam, 1968-1972; North Vietnam violations of Paris agreements; Congressional refusal to appropriate funds to South Vietnam; Bunker's impressions of U.S. intervention in Dominican Republic; open elections in Dominican Republic