In the wake of Ngô Đình Diệms downfall, notably in 1964-1965, institutions of the Hòa Hảo Buddhist community developed with an unprecedented pace. As a result, this brought many internal divisions in the community.
It was widely recognized that the Hòa Hảo congregation and followers contributed greatly to the economic development and security of the Hậu Giang area. Foreign observers and journalists noted the visible prosperity of An Giang as well as the unprecedented safety of this area, compared to other provinces in South Vietnam during wartime. For instance Newsweek reporter Francois Sully remarked that American advisers were able to travel throughout An Giang without any weapons except 35-mm cameras. Newsweek, August 30, 1965.
The Hòa Hảo community was keen to prevent infiltration of the Việt Cộng forces. Correspondingly, no considerable military presence was needed there even though An Giang garrison was smaller as compared to other provinces. Followers of Hòa Hảo Buddhism not only refused to pay taxes to the Việt Cộng forces but they also formed local self-defense units in order to combat the Communist infiltration and cut the Việt Cộng supply lines. John Haseman. The Hoa Hao, A Half Century of Conflict. Asian Affairs, July, 1976.
Inevitably, the Hòa Hảo community became politically involved. Representatives of the community took part in local and national elections. Notably, in 1965 only the Hòa Hảo followers were elected deputies of the provincial councils in An Giang and Châu Đốc, while in Kiến Phong, Vĩnh Long, Phong Dinh provinces, the adepts controlled some 80 percent of the seats in the provincial councils. In the National Assembly election of November 9, 1965, the Hòa Hảo representatives in An Giang were elected with the highest numbers of votes, in the nation. Subsequently, Hòa Hảo activists dominated electoral campaigns in these areas.
Moreover, the Hòa Hảo organization affiliated with a new political movement in the South. In April 1964, Dr. Nguyễn Xuân Chữ and Phan Bá Cầm initiated the creation of the National Revolutionary Movement, or Phong trào Cách mạng Dân tộc. However, it took several years to reconcile differences between potential members.
On May 15, 1968, a new organization - the Vietnams National Revolutionary Forces, or Lực lượng Cách mạng Dân tộc Việt - was finally launched. It included the Social-Democratic Party of the Hòa Hảo community and Vietnam Restoration League (Việt Nam Phục Quốc Hội), a political arm of the Caodaist community. The new group also included representatives of Đại Việt Quốc Dân Đảng, Đại Việt Duy Dân, Đại Việt Quốc Xã and Việt Nam Quốc Dân Đảng.
Following Nguyễn Xuân Chữs death in 1967, the new movement was headed by Phan Bá Cầm. Its members never joined any government until 1975 although they represented at least four million of Hòa Hảo and Cao Đài followers. It should be pointed out that the authorities of the Second Republic pursued oppressive policies aimed at the National Revolutionary Forces. After 1975, many leaders of this organization, notably Phan Bá Cầm, Tạ Nguyên Minh, Trần Quang Vinh, and Nguyễn Xuân Tiến perished in Communist prison camps. Other leaders, including Dương Như Thuấn and Phạm Quốc Trị, passed away in exile.
In short, during the 1964-1975 period, although the Hòa Hảo community had better opportunities for its development as compared to previous years, the congregation achieved only limited results, as the government of both, Communists and Republic officials were keen to obstruct the development of the Hòa Hảo movement.