Pan-Thaiism

Prior to the revolution of 1932, which replaced the absolute monarchy with a constitutional one, the Thai government had pursued good relations with the imperial powers, Britain and France, that ruled its neighbours: Burma, Malaya, Cambodia, and Laos; anti-colonial sentiment had been actively discouraged.

However, the military government that came to power in 1938, under Plaek Phibunsongkhram, actively sought to restore Thai "lost" territories; it also aggressively promoted pan-Thaiism.

[1] The intellectual architect of the new Thai nationalism was Wichit Wathakan.

The country officially changed its name from Siam to Thailand, with the word "Thai" being interpreted in an idiosyncratic way, not only referring to speakers of Central Thai (Siamese) or even Tai languages generally, but to all those who had once been under the Ayutthaya and Rattanakosin kingdoms.

Thai rule was not generally welcomed by the subject populations, however.