 The different visions in the meanings of concepts – democracy, community, security, and social change – were substantial, and were a key cause of the strains throughout their alliance.As the Buddhist crisis deepened in July 1963, non-communist Vietnamese nationalists and the military began preparations for a coup.Bùi Diễm, later South Vietnam's Ambassador to the United States, reported in his memoirs that General Lê Văn Kim requested his aid in learning what the United States might do about Diệm's government.