In 1941, a Comintern agent named Ho Chi Mihn formed the League for the Independence of Vietnam, better known as the Viet Mihn. This communist affiliated force fought against the Japanese, who were actually in control of French Indochina during WWII. While ostensibly administered by Vichy France, Imperial Japan was actually in charge on the ground with French bureaucrats doing their bidding. The OSS (US Office of Strategic Services) aided the Viet Mihn against the Japanese, but the Pentagon correctly saw this theatre as a sideshow, and refused to commit significant assets.
The Japanese eventually threw out and humiliated the Vichy French officials in the region and gave Vietnam nominal independence in the Greater East Asia Co-Prosperity Sphere. When Japan surrendered, they turned over Vietnam to the Viet Mihn.
The needs of the Cold War showed the US government that France was going to be critical to the vital European theatre, so no opposition was launched against French claims in Indochina. The independent Vietnamese government only lasted a few days before the British and Chinese occupied the region, and eventually allowed the French to return. Ho Chi Minh used the time to weaken nationalist opposition by assassinations and overt attacks.
Ho Chi Mihn and his followers fled into the mountains and began a guerrilla war as the French reoccupied Indochina, and after the defeat of the Nationalists in China, received aid from the People’s Republic of China and USSR. The eight-year war cost the French 94,000 dead and 40,000 captured. The basic French plan was to push the Viet Mihn to attack strong positions in remote locations, where French logistics were superior and the French forces could inflict stinging losses. The French were worn down by shortages of engineer barrier materials, poor road networks and limited amounts of mobile forces, unable to respond to each crisis in turn.
While most French actions resulted in victory, each loss was difficult to replace, while the Viet Mihn could afford even the heaviest losses. The French moved from attempts to control all of Indochina to attempts to control secure zones, and sweeps outside of those zones. The Viet Mihn increasingly possessed heavy weapons and supporting arms. The new French Commander, Henri Navarre, reported he was unable to produce victory in the war, but could still achieve a stalemate. He selected Dien Ben Phu as the site. This was an old Japanese airstrip with loyal tribes in the area. It was less than 10 miles from Laos and less than 200 from Hanoi, and was astride the main Viet Mihn supply route deeper south.
The French had missed the transition from guerrilla to mixed warfare, on the lines proposed by Mao, and thus found that at the end of a long supply line, their firepower wasn’t as great as that of General Giap. Mixed warfare was the phase when the guerrillas were able to field the beginnings of real armies. The response to guerrillas was to spread out to track them down, but with real army units available, the counter-guerrillas could not spread out without being vulnerable to the army forces, and if they concentrated to face the army, the guerrillas were unmolested. Even with covert US aid to deliver supplies to Dien Ben Phu, the French were unable to keep their forces fully combat ready, and they were eventually defeated one fortification at a time. The Viet Mihn were aided by overt Chinese support and were able to call on vast logistical aid. General Giap praised the performance of his 400 Soviet supplied GAZ trucks in keeping his forces supplied, even during the monsoon, which crippled French resupply attempts.
This French phase ended with Indochina broken into North and South Vietnam, Laos and Cambodia. This was a great complication, for the communist forces were always clear they were fighting for Indochina, not a specific country, while the West was hamstrung by international boundaries.
The outbreak of the Korean War finally ended US ambivalence over Vietnam. Now seen as part of the Soviet and Chinese plan to take over the Pacific Rim, US advisors were sent to Vietnam. During the overlapping period while the French were still in Vietnam and Korea was ongoing, March Battalion Korea was sent to fight with the UN forces in Korea, becoming a well regarded part of the US 2nd Infantry Division. It was later destroyed in Vietnam.
Please note that this article was prepared for us by a US journalist. As is the case with all historical writing, interpretation of events may vary.