The 2009 Perak constitutional crisis was a political dispute in Malaysia regarding the legitimacy of the Perak state government formed in February 2009. It began when three Pakatan Rakyat state legislators defected, causing a collapse of the state government. The Sultan of Perak then refused Menteri Besar Mohammad Nizar Jamaluddin's request to dissolve the state assembly and call for new elections. Instead, Barisan Nasional (BN), with support from the three defecting assemblymen, formed the new state government.
The BN state government's legitimacy and the Sultan's decision not to dissolve the state assembly was disputed vehemently by Pakatan Rakyat politicians. A series of battles in the courts ensued between Nizar and the new Menteri Besar (Chief Minister), Zambry Abdul Kadir. Ultimately, the Federal Court confirmed in February 2010 that Zambry was the lawful menteri besar.
The crisis in Perak began with the announcement by Barisan Nasional's Nasarudin Hashim of his desire to cross the floor to Pakatan Rakyat. This was then followed by the re-defection of Nasaruddin to Barisan Nasional, and the declaration by three Pakatan Rakyat representatives, Deputy Speaker Hee Yit Foong, senior state Executive Council member Jamaluddin Mohd. Radzi and Osman Jailu, of their intentions to sit as independents while supporting the Barisan Nasional in confidence matters. The Sultan granted an audience to the Prime Minister (who is the head of Perak Barisan Nasional); at this meeting the PM claimed that the Barisan Nasional had the support of the majority of peoples elected representatives in the State Assembly. The Sultan ordered the PM to prove he had a majority. The PM left and returned later (the same day) with 31 elected members of the State Assembly all of whom told the sultan that they had no confidence in the Pakatan Rakyat and that they would support a Barisan Nasional government. Prior to the defections, Pakatan Rakyat had 32 representatives while Barisan Nasional had 27 representatives. The defections meant that the state now has 28 Pakatan Rakyat representatives, 28 Barisan Nasional representatives, and 3 independent representatives who pledged confidence to Barisan Nasional.