Before the Revolution of 1932, the kingdom had no written constitution. The monarch was the originator of all laws and the head of the government. In 1932 the first written constitution was promulgated, expected to be the most important guideline of the kingdom. However when political disputes took place among the elites, the first military coup was effected in 1933. The first official constitution was removed, a new one was promulgated. The constitutions have traditionally been considered to be the symbol of 'democracy' in Thailand, despite many abrogations and changes.
All of Thailand's charters and constitutions have recognized a unified kingdom with a constitutional monarchy, but with widely differing balances of power between the branches of government. Most Thai governments have stipulated parliamentary systems; however, several of them also called for dictatorships, e.g., the 1957 Constitution. Both unicameral and bicameral parliaments have been used, and members of parliament have been both elected and appointed. The direct powers of the monarch have also varied considerably.