Parliamentary elections were held in Iraq on 15 December 2005, following the approval of a new constitution in a referendum of 15 October. Electoral system The elections took place under a list system, whereby voters chose from a list of parties and coalitions. 230 seats were apportioned among Iraq's 18 governorates based on the number of registered voters in each as of the January 2005 elections, including 59 seats for Baghdad Governorate. The seats within each governorate were allocated to lists through a system of Proportional Representation. An additional 45 "compensatory" seats were allocated to those parties whose percentage of the national vote total (including out of country votes) exceeds the percentage of the 275 total seats that they have been allocated. Women were required to occupy 25% of the 275 seats. The change in the voting system gave more weight to Arab Sunni voters, who made up most of the voters in several provinces. It was expected that these provinces would thus return mostly Sunni Arab representatives, after most Sunnis boycotted the previous election. Parties and coalitions The deadline for registering parties and coalitions closed on 28 October. The Electoral Commission announced that 228 lists had been registered, including 21 coalitions. The emerging Iraqi political scene has been marked by groups of established parties running on joint lists, often grouped on sectarian or ethnic grounds. These lists are not necessarily stable, as the parties sharing a list may be past or present rivals; the situation will be even more complicated for the December 2005 election because parties can form different alliances in different governorates. The landscape is currently fluid; what follows is a list of some of the more important parties and coalitions, with a focus on alliances that have shifted since the January 2005 election. United Iraqi Alliance (#555) This coalition, dominated by Shi'ite parties, was formed to contest the January 2005 election with the blessing of Ayatollah Ali al-Sistani, the most senior Shi'ite cleric based in Iraq. It won the most votes in that election and became the senior partner in the coalition government that ran Iraq for most of 2005. The UIA's main components were: The Supreme Council for the Islamic Revolution in Iraq (SCIRI) led by Abdul Aziz al-Hakim and the transitional Deputy President Adel Abdul Mahdi The Islamic Dawa Party led by transitional Prime Minister Ibrahim al-Jaafari The Iraqi National Congress of Ahmed Chalabi