The 1932 coup and the creation of a constitutional order

One focus of civilian discontent centred on a group of students who had been educated overseas and were deeply dissatisfied with the tight political control that Siam’s ruling families held over the country. Some of these students became politically radicalized during the course of their education in Europe in the 1920s and early ’30s. They were led by Pridi Phanomyong, a brilliant young lawyer studying in Paris, who became the leader of an organization of overseas Siamese students. He was closely associated with a career artillery officer, Luang Phibunsongkhram (Pibul Songgram), who was then studying military science in France. In 1927 Pridi and Phibunsongkhram formed the People’s Party, which became the nucleus of a revolutionary group plotting to overthrow Siam’s absolute monarchy. On their return to Siam the two men and their associates, who became known as the Promoters, built up a revolutionary following among students, nonroyal government officials, and military officers.

On June 24, 1932, while Prajadhipok was away from Bangkok, the Promoters staged a bloodless coup, seizing control of the army, imprisoning the royal officials who had constituted the ruling group, and persuading the king to agree to rule under a constitution. A State Council and National Assembly were established under the new government. Many members of the new government had not played a direct part in the coup, and some were quite conservative in their political thinking. In early 1933, when Pridi drew up an economic plan for the country that was far more radical than many members of the new government could accept, feelings ran so high that the king was forced to suspend the National Assembly. The military leaders, fearing that the royalists would regain control of the government, forced the reconstitution of the National Assembly, which was followed by an attempted royalist countercoup in October 1933 under Prince Boworadet (Bavoradej), a cousin of the king. Although there was no evidence of royal collusion, Prajadhipok found his position untenable. In early 1934 he left for England, and in March 1935 he abdicated. A regency council was appointed to act for his successor, Prince Ananda Mahidol, then a schoolboy studying in Switzerland, until he came of age.

Although it never actually confronted an external threat until 1941, the new military, led by well-trained, disciplined officers and equipped with modern weaponry, contributed to a fundamental restructuring of power within the country. The 1932 revolution succeeded only because it was supported by military units led by nonroyal officers. Between 1933 and the end of 1938 the military grew ever stronger. The years just before World War II were marked by a tripling of the military budget, the establishment (1934) and subsequent spread of a paramilitary youth movement with fascist overtones, and a growing alliance with Japan.

The Phibunsongkhram dictatorship and World War II

In December 1938 Phibunsongkhram took over as military dictator, and the following year he changed the name of the country from Siam to Thailand. He embarked on a strongly nationalistic policy that was chauvinistic and anti-Chinese at home and irredentist and pro-Japanese abroad, and he set out to elevate the position of the military—especially the army, in which he held the rank of field marshal—and to portray it as the defender of the country. Luang Wichit Watthakan, Phibunsongkhram’s influential ideologist, drew on a Japanese prototype for his ideal of wiratham, the “code of the warrior,” as the foundation for Thai nationalism. In November 1940, taking advantage of the defeat of France by Germany the previous June, Phibunsongkhram ordered the invasion of French territories in western Laos and northwestern Cambodia that formerly had been under Thai control. Japan supported Thai claims to the disputed lands.

Thailand’s leaders nonetheless sought help from Britain and France against an increasingly aggressive Japan, but the British were too deeply involved in Europe to provide them with meaningful support. On December 8, 1941—following the Japanese attack on Pearl Harbor, Hawaii—Japanese troops entered Thailand and requested the right of passage through the country to facilitate their planned surprise rear attack on British-held Singapore. After a brief fight against the advancing Japanese, all Thai troops were ordered by Phibunsongkhram to lay down their arms, and Thailand subsequently signed a full Treaty of Alliance with Japan; in January 1942 the Thai government declared war on Britain and the United States.

Thailand gained minor territorial concessions in Burma (Myanmar) and Malaya, as well as in Laos and Cambodia, from its wartime alliance with Japan, but the Thai economy suffered greatly, ultimately undermining public confidence in Phibunsongkhram. From 1942 onward, overseas resistance groups based in the United States and Britain made contact with similar groups within Thailand led by Pridi Phanomyong, then serving as regent in the absence of the young king Ananda. The Free Thai, as these groups were collectively known, conducted raids against the Japanese and succeeded in infiltrating the government. In July 1944 Phibunsongkhram was forced to resign, and in August 1945 Japan surrendered.