(June 24, 1932) in the history of Thailand, a bloodless coup that overthrew the Thai king, put an end to absolute monarchy in Thailand, and initiated the so-called Constitutional Era. The coup was headed by a group of men often referred to as the “promoters.” They included members of the Thai elite, noted intellectuals, some European-educated, and disaffected army officers; among the key “promoters” were Pridi Phanamyong and Phya Phahon Phonphayuhasena.

As the traditional pattern of life in Thailand changed drastically under the impact of Western ideas, opposition to the institution of monarchy had grown among officials and the intelligentsia. The revolution brought about first a Temporary Constitution, which stripped the king of his powers and then vested them nominally in the people but actually in the small group of Promoters, calling itself the People's Party. In effect, the Temporary Constitution was a party dictatorship cloaked under constitutional forms.

The Permanent Constitution, which came into effect in December 1932, partially restored some measure of prestige and dignity to the crown, although the king's actual power was nominal. Royal princes were excluded from membership in the State Council and the Assembly, a partially elected, partially appointed body with legislative power as well as the power of constitutional interpretation. In effect, however, the constitution was a facade used to justify the coup. A number of liberal Western-type reforms were espoused, but more direct means of control were preferred to constitutional representative government; a majority of the Siamese people did not understand this concept or remained indifferent to it.

After the 1932 coup Thailand had a long succession of constitutions and governments. None of the constitutions, however, effectively limited political power or provided a means by which political contests could be decided.