Catholic theology
Catholic belief holds that the church exists both on earth and in heaven simultaneously, and thus the Virgin Mary and the saints are alive and part of the living church. Prayers and devotions to Mary and the saints are common practices in Catholic life. These devotions are not worship, since only God is worshiped. The church teaches that the saints "do not cease to intercede with the Father for us. ... So by their fraternal concern is our weakness greatly helped."
1963 South Vietnamese coup
South Vietnam's Buddhist majority had long been discontented with Diệm's strong favoritism towards Roman Catholics. Public servants and army officers had long been promoted on the basis of religious preference, and government contracts, US aid, business favours and tax concessions were preferentially given to Catholics. The Roman Catholic Church was the largest landowner in the country, and its holdings were exempt from land reform (i.e., appropriation). In the countryside, Catholics were "de facto" exempt from performing corvée labour and in some rural areas, it was claimed that Catholic priests led private armies against Buddhist villages. In 1957, Diệm dedicated the nation to the Virgin Mary.