Thailand was an absolute Monarchy until 1932 when it changed to a constitutional monarchy and created its first constitution. Since then, due to a high level of political instability and a frequency of military coups, Thailand has had 17 charters and constitutions. From 1992 until the 2006 military coup, the country functioned as a democracy with constitutional changes of government. In 2007, the constitution was amended and ratified by public referendum returning the country to a democracy. The changes to the constitution outlined a bicameral system of government with some members elected and others appointed. These changes to the constitution have been a point of contention between two factions in Thailand, resulting in public demonstrations and civil unrest. Despite these disturbances, elections still progress in a constitutional fashion, with the last occurring in July 2011.

The King, King Bhumibol (Rama IX), is the Head of State but does not have much formal power, being recognised simply as a symbol of national identity and unity. The Prime Minister is Head of Government and leads a parliament, based on the Westminster two-party system. The Senate is comprised of 150 members, 76 of whom are popularly elected. The House of Representatives has 480 members with 400 popularly elected.