During the Second World War a pro-Vichy regime, headed by Admiral Decoux as Governor-General, continued to exercise administrative control over the countries of French Indochina. It did so at the pleasure of the Japanese, who permitted this exercise of apparent French sovereignty in exchange for what Tokyo saw as a vital concession to its interests: the unfettered opportunity to move troops unhindered through the countries of Indochina and to use their territory for the stationing of its aircraft. The Japanese aircraft that sank the British battleships Prince of Wales and Repulse in December 1941, leaving Malaya and Singapore without naval protection, took off from airfields in Cambodia. Then, as the tide of battle began to swing decisively against them, the Japanese in March 1945 no longer saw any benefit in allowing the French to exercise even the constrained power they had retained to this point. In a swift and effective coup de force they overturned the Decoux regime and embarked on a belated effort to promote 'independent' states in Laos, Cambodia and Vietnam, while maintaining effective control over all three countries.SOURCE: The Mekong: Turbulent Past, Uncertain Future, by Milton Osborne (Grove Press, 2000), pp. 177-178
This was a climactic moment, for it was recognised, most particularly in Vietnam, as a sign that French colonialism's days were numbered. From this point on, and with the Vietnamese communists led by a remarkable set of talented individuals of whom Ho Chi Minh was only one, the stage was slowly being set for three decades of bitter hostilities, the years of the First and Second Indochina Wars. First the French and then the Americans sought to stem the tide of communist revolution but, as hindsight has made crystal clear, their efforts failed and the countries along the Mekong that once made up Indochina all finally came under communist control in 1975.