Thailand's foreign policy has been little studied. This is perhaps because, just as Britain is sometimes said to have no climate, only weather, a consistent Thai foreign policy stance cannot always be readily discerned. Inconsistency, or perhaps simply an overarching pragmatism, has been a recurrent feature of Siam/Thailand's dealings with the wider world. Such pragmatism was perhaps most explicitly seen during World War II, when the Phibun Songkhram government formed an alliance with Japan and declared war on the United States. However, Seni Pramoj, then ambassador to Washington, failed to deliver the declaration. When the Allies emerged as victors, Thailand was quick to claim that the pro-Allied “Free Thai” resistance movement had represented the real stance of the war-time nation, an argument which was broadly accepted by the Americans. In other words, Thailand succeeded in being on both sides during World War II, a rare feat of foreign policy flexibility. Not for nothing has the Thai Foreign Ministry traditionally prided itself on a mastery of “bamboo diplomacy”.

By the 1980s, however, such diplomacy was coming under strain. Whereas both the pre-1932 absolute monarchy and the military-dominated post-1932 regimes were characterized by the concentration of power in the hands of a tiny elite, with elite diversification came a new form of inconsistency: the pursuit of different policies by different ruling groups. This was most clearly seen during the ill-fated Chatichai Choonhavan government of 1988–91, which saw a struggle for control of foreign policy towards Indochina. An elected prime minister with a group of well-educated and iconoclastic advisers — the so-called Ban Phitsanulok team — sought to engage with Vietnam and end the isolation of Cambodia, turning the former battlefield of Indochina into a marketplace. Meanwhile the Foreign Ministry remained wedded to the Americaninfluenced ASEAN orthodoxy of punishing Vietnam for the “crime” of invading Cambodia in 1979, while the Thai military took matters a stage further by actively supporting residual elements of the Khmer Rouge.