In the late 1920s, 3 separate communist parties, namely the Annamese Communist Party, Indochinese Communist Party and the Indochinese Communist Union, were formed under the influence of Marxism with the help of Ho Chi Minh – a Comintern (the Communist International) agent who was expected to help build Communist movements in Southeast Asia. They were then followed by Tạ Thu Thau’s Trotskyist movement.
In 1930, Ho Chi Minh, under the name of Nguyen Ai Quoc, went to Hong Kong to unite all the 3 parties into the Vietnamese Communist Party, later renamed to Indochinese Communist Party. On May 19, 1941, he formed the League for the Independence of Vietnam (abbreviated to Viet Minh Front) at Pac Bo. The Viet Minh was dominated by the Communist Party although it was supposed to be an umbrella group for all parties fighting for Vietnam’s independence.
In a power struggle in 1945, the Viet Minh purged and killed members of rival groups, such as the leader of the Constitutional Party, the head of the Party for Independence, some Trotskyists and Ngo Dinh Diem’s brother, Ngo Dinh Khoi. In July 1946, hundreds of political opponents, notably members of the the Nationalist Party of Greater Vietnam, were jailed or exiled after a failed attempt to raise a coup against the Viet Minh Government. In the same year, when Ho Chi Minh travelled abroad, his subordinates jailed around 2,500 non-communist nationalists and forced 6,000 others to flee. All rival political parties were hereafter banned and local governments were purged to minimize opposition later on. The communists eventually suppressed all non-communist parties. North Vietnam became a single-party state under communist rule since then.
However, it was striking that the first Congress of Democratic Republic of Vietnam, after Ho Chi Minh’s Declaration of Independence of Vietnam on September 2, 1945, had over two-third of its members come from non-Viet Minh political factions, some without election.
It is also worth to notice that following World War I, Ho Chi Minh (under the name of Nguyen Ai Quoc) had petitioned U.S. President Woodrow Wilson to help remove and supplant the French with a new and nationalist Vietnamese government. On February 28, 1946, he penned a letter to U.S. President Harry S. Truman, asking him for the U.S. support once again in gaining independence for Vietnam. Apparently both requests were ignored. These failures likely further radicalized Ho Chi Minh, making him believe Communism is the right choice for him and his country to gain independence. Throughout his actions, it is likely that Ho Chi Minh was not an extreme communist. He later also confirmed that it was patriotism, not communism, that inspired him.