The head of state and commander-in-chief of the armed forces is the president, who is elected by popular vote for a maximum of 2 four-year terms on the same ticket as the vice-president. The president appoints the members of the Executive Yuan as their cabinet, including a premier, who is officially the President of the Executive Yuan; members are responsible for policy and administration. The main legislative body is the unicameral Legislative Yuan with 113 seats. Seventy-three are elected by popular vote from single-member constituencies; thirty-four are elected based on the proportion of nationwide votes received by participating political parties in a separate party list ballot; and six are elected from two three-member aboriginal constituencies. Members serve four-year terms. Originally the unicameral National Assembly, as a standing constitutional convention and electoral college, held some parliamentary functions, but the National Assembly was abolished in 2005 with the power of constitutional amendments handed over to the Legislative Yuan and all eligible voters of the Republic via referendums. The premier is selected by the president without the need for approval from the legislature, but the legislature can pass laws without regard for the president, as neither he nor the Premier wields veto power. Thus, there is little incentive for the president and the legislature to negotiate on legislation if they are of opposing parties. After the election of the pan-Green's Chen Shui-bian as president in 2000, legislation repeatedly stalled because of deadlock with the Legislative Yuan, which was controlled by a pan-Blue majority. Historically, the ROC has been dominated by strongman single party politics. This legacy has resulted in executive powers currently being concentrated in the office of the president rather than the premier, even though the constitution does not explicitly state the extent of the president's executive power. The Judicial Yuan is the highest judicial organ. It interprets the constitution and other laws and decrees, judges administrative suits, and disciplines public functionaries. The president and vice-president of the Judicial Yuan and additional thirteen justices form the Council of Grand Justices. They are nominated and appointed by the president, with the consent of the Legislative Yuan. The highest court, the Supreme Court, consists of a number of civil and criminal divisions, each of which is formed by a presiding judge and four associate judges, all appointed for life. In 1993, a separate constitutional court was established to resolve constitutional disputes, regulate the activities