Initial colonization of what is now Papua New Guinea evolved as part of a competition between Great Britain and Imperial Germany in the 1800s over Pacific Island possessions.
After World War I (1914–18), Germany lost all its Pacific colonies; in 1921, what had been German New Guinea became a Mandated Territory of the League of Nations, administered by Australia. The Mandated Territory consisted of the northeastern portion of the mainland, together with islands as far east as Bougainville. Australia retained control of the Territory of Papua, the southeastern portion of the mainland, and smaller adjacent islands. The Mandated Territory was distinctive for its greater prosperity, based on coconut plantations mostly operated by Australian firms and individuals. Papua had a small administrative budget and a paternalistic policy aimed at protecting the indigenous population from being exploited.
Japan's invasion of the Pacific in World War II (1939–45) carried as far into PNG as the occupation of the north coast of the main island, and of New Britain and Bougainville. Allied counterattacks on Japanese positions brought destruction of property and considerable loss of life to the local people in these areas. During the war, both Papua and the Mandated Territory were administered as a single political unit, and this continued after military operations ended. Technically, the legal status of Papua remained distinct from that of New Guinea, which became officially a Trust Territory of the United Nations with Australia as trustee. However, the postwar Australian government treated the entire area as the single Territory of Papua and New Guinea.
Beginning in the 1960s, Australia came under considerable international pressure to grant independence to both Papua and New Guinea as a single nation. At that time, there had been little development of political and social institutions, of the kind that would have made transition to independence an easy one. All real political authority was in the hands of Australians; Papua New Guineans (as they began to be called) occupied only the lowest echelons of the public service.
This would begin to change rapidly beginning in 1964 with the establishment of the first elected legislative body, the House of Assembly, empowered to enact legislation affecting the whole territory. Voting for the House of Assembly was the first experience of this kind for most of the indigenous population, and it launched the first steps toward the independence that was achieved in September 1975. At that time, the independent state of Papua New Guinea was established as a constitutional monarchy and a member of the British Commonwealth, with the British sovereign as head of state.
Papua New Guinea is governed by the so-called Westminster system. This means that an elected Parliament is the national legislative authority. Parliament consists of 109 members chosen by universal adult suffrage for five-year terms; 89 of these are elected from local constituencies. The rest are elected from each of the nation's 19 provinces and the National Capital District (NCD) centered in Port Moresby. Executive authority resides in the prime minister and cabinet, all of whom are elected members of Parliament (MPs). The prime minister must demonstrate that he commands the support of a majority of MPs in order to form a cabinet. In Britain, where the Westminster system originated, this works smoothly enough because of long traditions, well-established and disciplined political parties, and an independent public service. However, these conditions do not exist in Papua New Guinea, leading to a degree of political instability that has attracted international concern.
Traditionally, indigenous politics operated on a very small scale in what became PNG. Few of the many language groups had what could be recognized as true chiefs with authority over large groups. Today many people still recognize first loyalties to a clan, an influential individual, or at most a language or geographic area. One consequence is large numbers of candidates, with no more than nominal party affiliation, running for Parliament in a single electorate. The successful candidate does not have to get a majority of votes cast. In 1992, 87 of the winning candidates received less than 30% of the votes cast in their respective races. In such cases, MPs can hardly expect to enjoy the respect or long-term support of those they are supposed to represent. It is not surprising that each election sees a high turnover of MPs.
A Westminster system depends on the existence of a relatively small number of well-organized political parties, but in PNG even the most successful parties have difficulty commanding a majority in Parliament. Coalition governments have been the rule since independence. In 1997, 39 MPs were elected as Independents, without party affiliation or loyalty. The head of a party cannot even count on other MPs in his own group to back his attempt to form a government. Party switching is one of the most common features of PNG politics. This can lead to votes of no confidence in the governing prime minister, which makes formation of a whole new government necessary. No prime minister has ever served a full five-year term.