The politics of Armenia take place in the framework of the parliamentary representative democratic republic of Armenia, whereby the president of Armenia is the head of state and the prime minister of Armenia the head of government, and of a multi-party system. Executive power is exercised by the president and the Government. Legislative power is vested in both the Government and Parliament. History Armenia became independent from the Russian Empire on 28 May 1918 as the Republic of Armenia, later referred as First Republic of Armenia. About a month before its independence Armenia was part of short lived Transcaucasian Democratic Federative Republic. Suffering heavy losses during the Turkish invasion of Armenia and after the Soviet invasion of Armenia, the government of the First Republic resigned on 2 December 1920. Soviet Russia reinstalled its control over the country, which later became part of the Transcaucasian SFSR. The TSFSR was dissolved in 1936 and Armenia became a constituent republic of the Soviet Union known as the Armenian SSR, later also referred as the Second Republic of Armenia. During the dissolution of the Soviet Union the population of Armenia voted overwhelmingly for independence following the 1991 Armenian independence referendum. It was followed by a presidential election in October 1991 that gave 83% of the votes to Levon Ter-Petrosyan. Earlier in 1990, when the National Democratic Union party defeated the Armenian Communist Party, he was elected Chairman of the Supreme Council of Armenia. Ter-Petrosyan was re-elected in 1996. Following public discontent and demonstrations against his policies on Nagorno-Karabakh, the President resigned in January 1998 and was replaced by Prime Minister Robert Kocharyan, who was elected as second President in March 1998. Following the assassination of Prime Minister Vazgen Sargsyan, parliament Speaker Karen Demirchyan and six other officials during parliament seating on 27 October 1999, a period of political instability ensued during which an opposition headed by elements of the former Armenian National Movement government attempted unsuccessfully to force Kocharyan to resign. In May 2000, Andranik Margaryan replaced Aram Sargsyan (a brother of assassinated Vazgen Sargsyan) as Prime Minister. Kocharyan's re-election as president in 2003 was followed by widespread allegations of ballot-rigging. He went on to propose controversial constitutional amendments on the role of parliament. These were rejected in a referendum the following May. Concurrent parliamentary elections left Kocharyan's party in a very powerful position in the parliament. There were mounting calls for the President's