The Franco-Thai War of 1940-1941 Volume 1

Following in the footsteps of the border conflicts between France and Siam at the end of the nineteenth century over control of Laos and Cambodia, the Franco-Thai crisis of the winter of 1940–1941 was the culmination of tensions that had gradually resurfaced over the course of eight years: from June 1932, following the emergence of a nationalist military regime in Bangkok, to June 1940, following France’s defeat.

The isolation of Vichy-controlled Indochina resulting from the armistice encouraged Japan to establish a foothold in Tonkin as part of its war against China. In Bangkok, although the Empire of the Rising Sun was regarded as a friendly nation, the bloody military action carried out by the Imperial Japanese Navy (IJN) at Lang Son was viewed with alarm. What if Tokyo decided to press its advantage and seize control of the whole of Indochina?

Such a development would put an end to Thailand’s hopes of one day recovering its “lost territories” of Laos and Cambodia, which its political leaders had never forgotten.

Encouraged by the irredentist faction within his regime, as well as by the British, who preferred to see the Thais occupying these two Vichy-controlled territories rather than the Japanese, Prime Minister General Phibun Songkhram recognised the weakening of the French position in Indochina. He understood that this was a historic opportunity, one that might never present itself again.

With the French dragging their feet over their pre-war commitment to revise the Mekong border, the Thai dictator put forward territorial claims over Laos and Cambodia, hoping that the French would give way. However, once again overestimating their military capabilities, the French remained uncompromising.

Meanwhile, a series of incidents broke out along the border, with each side blaming the other. Until one of these incidents finally ignited the powder keg…