liberal democracies. There are also self-proclaimed republics that act similarly to absolute monarchies with absolute power vested in the leader and passed down from father to son. North Korea and Syria are two notable examples where a son has inherited political control. Neither of these states are officially monarchies. There is no constitutional requirement that power be passed down within one family, but it has occurred in practice. There are also elective monarchies where ultimate power is vested in a monarch, but the monarch is chosen by some manner of election. A current example of such a state is Malaysia where the Yang di-Pertuan Agong is elected every five years by the Conference of Rulers composed of the nine hereditary rulers of the Malay states, and the Vatican City-State, where the pope is selected by cardinal-electors, currently all cardinals under the age of 80. While rare today, elective monarchs were common in the past. The Holy Roman Empire is an important example, where each new emperor was chosen by a group of electors. Islamic states also rarely employed primogeniture, instead relying on various forms of election to choose a monarch's successor. The Polish–Lithuanian Commonwealth had an elective monarchy, with a wide suffrage of some 500,000 nobles. The system, known as the Golden Liberty, had developed as a method for powerful landowners to control the crown. The proponents of this system looked to classical examples, and the writings of the Italian Renaissance, and called their elective monarchy a rzeczpospolita, based on res publica. Sub-national republics In general being a republic also implies sovereignty as for the state to be ruled by the people it cannot be controlled by a foreign power. There are important exceptions to this, for example, republics in the Soviet Union were member states which had to meet three criteria to be named republics: be on the periphery of the Soviet Union so as to be able to take advantage of their theoretical right to secede; be economically strong enough to be self-sufficient upon secession; and be named after at least one million people of the ethnic group which should make up the majority population of said republic. It is sometimes argued that the former Soviet Union was also a supra-national republic, based on the claim that the member states were different nation states. The Socialist Federal Republic of Yugoslavia was a federal entity composed of six republics