Thailand, known as Siam until 1939, was the only nation in Southeast Asia to avoid direct colonization. During World War II, Thailand was sympathetic to the Axis Powers and supported Japan to avoid colonization. Initially governed as an absolute monarchy, a series of military coups limited the power of the king in 1932. Siam became a constitutional monarchy and was renamed Thailand in 1939 to reflect a movement toward modernization. King Bhumipol Adulyadej, monarch since 9 June 1946, plays a largely ceremonial role, but his opinions are highly regarded and his influence on politics is significant. His major influence and power stems from his role in dealing with political crises by granting or withholding legitimacy. In 1996, King Bhumipol celebrated his 50-year golden jubilee, making him the longest reigning monarch in the world. December 5, his birthday, is a national holiday.
Thailand has a long history of military regimes and military intervention in politics. There have been at least 18 coups and attempted coups since 1932. The three decades following World War II (1950s, 1960s, and 1970s) were characterized by authoritarian rule. Gradually, however, Thailand evolved toward a semi-democratic government that showed high levels of instability until a coalition of civilian parties led by Chuan Leepai won power in 1992.
The Thai Parliament approved a new Constitution on 11 October 1997. Drafted by a 99-member charter committee, the document is, by far, Thailand's most democratic Constitution. It requires the prime minister be an elected member of Parliament. It continues the tradition of a bicameral Parliament with a 500-member House of Representatives (400 elected from geographic districts and 100 from a national list). Contrary to earlier Constitutions that provided for an appointed Senate, the new Senate of 200 members is elected nationally from throughout the country. As before, elections for prime minister are held every four years or whenever Parliament is dissolved. The leader of the party that gains the most seats in an election is charged with forming a government and presenting the list of cabinet members to the king for formal approval. The basic goal of the 1997 Constitution was to reduce the influence of money in politics and to make Thailand a more genuinely democratic society with greater local involvement.