Article 50 states that there are States General and that these represent the whole of the people of the Netherlands. Thus a clear distinction is made to the situation under the confederal Dutch Republic when the States General represented the provinces. Doctrine holds that the article also entails that political parties have to give priority to the public interest, as opposed to the particular interests of their constituents. Article 51 specifies that the States General consist of a House of Representatives of the Netherlands (lower house), the Second Chamber of 150 members and a Senate (upper house), the First Chamber of 75 members — the constitution deliberately mentions the House of Representatives first to emphasize its political primate. Subarticle 4 mentions that both Houses can gather in an indivisible United Assembly of 225 members, a joint session necessary to perform some acts, such as the appointment of a new King in absence of royal heirs. When in United Assembly the President of the Senate is President of the States General (Article 62); the House of Representatives has tried to change this in the revision of 1983 but has twice been defeated by the Senate defending its privilege. The Houses sit for four years (Article 52). They are elected on basis of proportional representation (Article 53) and by a secret ballot (Subarticle 2). The House of Representatives is elected by all Dutch citizens over the age of eighteen (Article 54), except those who have been disqualified by a court sentence as part of their punishment for a crime or those who have been declared incapable by court because of insanity (Subarticle 2). Formal law can limit the right to vote to resident nationals only but presently does not. The Senate is elected by the States Provincial (Article 55).