A dominant-party system, or one party dominant system, is a party system where only one political party can realistically become the government, by itself or in a coalition government. Under what has been referred to as "electoralism" or "soft authoritarianism", opposition parties are legally allowed to operate, but are too weak or ineffective to seriously challenge power, perhaps through various forms of corruption, constitutional quirks that intentionally undermine the ability for an effective opposition to thrive, institutional and/or organizational conventions that support the status quo, or finally, and most controversially, inherent cultural values averse to change.
Not all dominant-party systems are undemocratic. In many cases, such as the presidency of Hugo Chávez in Venezuela or the government of Tommy Douglas in the Canadian province of Saskatchewan, sheer populism can keep the momentum of a government going for quite some time. In other cases, sheer inertia preserves the dominant party, as with the Liberal Democratic Party in Japan, where some argue the Japanese people as well as Japanese special interests have gotten so accustomed to LDP rule that until quite recently they might have found it hard to imagine it any other way.
Thus in contrast to single-party systems, which are almost always authoritarian, dominant-party systems can occur within a context of a democratic system. In a single-party system other parties are banned, but in dominant-party systems other political parties are tolerated, and (in democratic dominant-party systems) operate without any impediment, but do not have a realistic chance of winning; the dominant party genuinely wins the votes of the vast majority of voters every time (or, in authoritarian systems, claims to).
In some states opposition parties are subject to varying degrees of official harassment and most often deal with restrictions on free speech (such as press clubs), lawsuits against the opposition, rules or electoral systems (such as gerrymandering of electoral districts) designed to put them at a disadvantage. In some cases outright electoral fraud keep the opposition from power. On the other hand, some dominant-party system occur in countries that are widely seen, both by their citizens and outside observers, to be textbook examples of democracy. The reasons why a dominant-party system may form in such a country are often debated: Supporters of the dominant party tend to argue that their party is simply doing a good job in government and the opposition continuously proposes unrealistic or unpopular changes, while supporters of the opposition tend to argue that the electoral system disfavors them (for example because it is based on the principle of first past the post), or that the dominant party receives a disproportionate amount of funding from various sources and is therefore able to mount more persuasive campaigns.
The Canadian province of Alberta has been ruled continuously by the Progressive Conservatives since August 30, 1971. Prior to that, the Social Credit Party held power for 36 years starting on August 22, 1935.
Fianna Fáil have been the dominant government party since 1987, except for a 30-month period in 1994-1997. The next election is scheduled for 2012, by which time the party will have held power for 23 of 25 years.
The Partit Nazzjonalista has democratically been the sole governing party in Malta since 1987, except for a brief 22-month period between 1996 and 1998. It won elections held in 1987, 1992, 1998, 2003 and 2008, each time defeating the left-of-centre Malta Labour Party. Since 1966 there have only been these two parties represented in the Maltese Parliament.
Demokratska Partija Socijalista Crne Gore (founded 1943, Savez Komunista Crne GoreSKCG up to 22 June1991, Komunistička Partija Crne GoreKPCG up to 1952)
In Sweden, the Social Democrats have been the ruling party almost constantly since World War II. All party leaders since 1907 have served as Prime Minister at some point. In 2006 a right-wing government was elected, but only after its component parties moved their policies significantly to the left.
Former dominant-party systems
Countries which have since lost their one party dominance include:
The Norwegian Labour Party ruling from 1935 to 1965, though it has been the biggest party in Norway since 1927 and has been in power many other times.
The Liberal-Country Party Coalition government of Australia between 1949 and 1972 can also be considered an example of a former dominant party system.
Since 1896, the Liberal Party of Canada has held either majority or minority control of the government for 79 out of 111 years, not including four years of coalition government from 1917-21. The Progressive Conservatives and the Conservatives have held outright majorities for only 24 years in the same timespan, though the Conservatives do currently hold power in Parliament, albeit in a minority government. Inclusion of the Liberals is debatable, as even during long stretches of electoral losses (between 1963 and 1984 for example) the Progressive Conservatives were seen by the media and the public as real contenders for government.
The Colorado Party of Paraguay from 1880-1904 and then 1947-2008. They were the sole legal party from 1947-1962.