The Japanese surrendered to the Allies in August 1945, and the Communist Viet Minh under Ho Chí Minh aimed to take power. Due to the Japanese associations, Ho was able to persuade Bao Dai to abdicate on August 25, 1945, handing power to the Viet Minh — an event that greatly enhanced Ho's legitimacy in the eyes of the Vietnamese people. Bao Dai was appointed “supreme adviser” in the new government in Hanoi, which asserted independence on September 2.
As his country descended into violence — rival Vietnamese factions clashing with each other and with the French — Bao Dai left the country after a year in the “advisory” role, living in Hong Kong and China. The French persuaded him to return in 1949 as leader and Emperor. But the war between the French colonial forces and the Viet Minh continued, ending in 1954 shortly after a major victory for the Viet Minh at the Battle of Dien Bien Phu.
The USA, nervous since the war of Ho Chí Minh’s communism, became strongly opposed to the idea of a Vietnam run by Ho; after his government of the north, the Democratic Republic of Vietnam, in 1950 gained recognition from the Soviet Union and China. In the south in the same year, the French formed a rival Vietnamese government under Bao Dai in Saigon which was recognized by the United States and Great Britain, but did not enjoy wide popular support.
The 1954 peace deal between the French and the Viet Minh involved a Chinese-inspired, supposedly temporary partition of the country into North and South. Bao Dai had intentions to take full control of South Vietnam, and from his home in France appointed the religious nationalist Ngô Dình Diem as Prime Minister. However, in 1955 Diem used a referendum to remove the Emperor and took control of the South himself, managing to win American support.
On March 20, 1934, at the imperial city of Hue, Bao Dai married Jeanne Marie-Thérèse (Mariette) Nguyen Huu-Hao Thi Lan (1914-1963), who was renamed Hoang Hau Nam Phuong, or Empress of the South. A daughter of Pierre Nguyen Huu-Hao, Duke of Long-My, she died in 1968. They had four children, including a daughter, Princess Phuong Mai, who married Don Pietro Badoglio, 2nd Duke of Addis Ababa and Marquess of Sabotino.
Bao Dai had four other wives, three of whom he married during his marriage to Nam Phuong: Phu Anh, a cousin, whom he married circa 1935; Hoang, a Chinese woman, whom he married in 1946 (one daughter); Bui Mong Diep, whom he married in 1955 (two children); and Monique Baudot, a French citizen whom he married in 1972 and whom he first created Princess Vinh Thuy then renamed Thai Phuong Hoang-Hau.