A series of political demonstrations and following unrest occurred in Thailand from 26 March to 14 April 2009 in Bangkok and Pattaya against the government of Abhisit Vejjajiva and the military crackdown that followed. Up to 100,000 people demonstrated in central Bangkok at the height of the protests.
On 17 December 2008, Abhisit Vejjajiva, leader of the Democrat Party, was named Prime Minister, after the Constitutional Court of Thailand banned then-Prime Minister Somchai Wongsawat from politics for five years. In March 2009, Thaksin Shinawatra claimed via video broadcast that Privy Council President Prem Tinsulanonda masterminded the 2006 military coup, and that Prem and fellow Privy Councilor members Surayud Chulanont and Chanchai Likhitjittha conspired with the military to ensure that Abhisit became Premier. Although Abhisit denied the accusations, thousands protested in Bangkok in early April demanding that Abhisit resign from the Premiership and that Prem, Surayud, and Chanchai resign from the Privy Council. Thaksin called for a "peoples revolution" to overcome the alleged aristocratic influences of the Abhisit government. The protests, led by the red-shirted National United Front of Democracy Against Dictatorship (UDD) expanded to Pattaya, the site of the Fourth East Asia Summit. Violent clashes occurred between the UDD and blue-shirted government supporters affiliated with Newin Chidchob. The protests caused the summit to be cancelled, leading Abhisit to declare a state of emergency in the areas of Pattaya and Chonburi on 11 April.