The other day my friends and I gathered in the college dorm and expressed grievances about our electoral systems. Those from countries where one or two parties dominate the legislature were frustrated with their country's politics. They lamented that since the two parties currently in power would have to pass legislation to transition into a multi-party friendly system, it would never happen.

Has such change never happened in modern history? Was there at least one instance where a country ditched an electoral system favoring two parties such as First Past The Post and moved onto a more inclusive system such as Proportional Representation?

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    Switzerland switched in 1919. Is that modern enough to warrant an answer?
    – meriton
    Commented Dec 19, 2023 at 2:47
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    Are you asking about "two-party systems", or also multi-party systems with two parties which can be argued to dominate? That's not exactly the same question.
    – einpoklum
    Commented Dec 19, 2023 at 14:45
  • It will be interesting to see whether the UK becomes an example in the coming years. The Labour Party, which is all but guaranteed to form a government at the next election, is more interested than ever in electoral reform, but it's still up in the air. By the way, would you be interested in examples where only one chamber in a bicameral legislature experienced such a shift?
    – J.G.
    Commented Dec 20, 2023 at 10:09
  • FYI, in a multiparty system small parties get disproportional influence, which also is very frustrating.
    – d-b
    Commented Dec 20, 2023 at 11:55
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    All parties that are not in power are in favour of changing the system, until they get into power, and somehow 'forget' what they wanted.
    – Neil
    Commented Dec 20, 2023 at 15:45

4 Answers 4


New Zealand switched from first-past-the-post to "mixed member proportional representation (MMP)" starting in the 1996 election (https://nzhistory.govt.nz/politics/fpp-to-mmp).

Seats won by each party in elections, 1938–2023:

![enter image description here

From 1938 through 1993, the National + Labour share of seats was at least 96% and often 100%.

From 1996, it was usually below 80% and at most 85% (2017). Also, in all elections except 2020, no single party had a majority of the seats.

As Shugart and Tan (2016) state:

New Zealand ... has moved away from two-party dominance to a multi-party parliamentary system

(Spreadsheet with sources)

France and Israel have never made a "successful shift from a two-party system to a multi-party system". They have always been multi-party systems.

(For France, the most recent legislative election where the two leading parties won more than 90% of the seats was 1863, during the Second Empire.)

enter image description here

The US (not depicted above) is the prototypical two-party system, where the two leading parties have since 1945 won at least 99.5% of the seats in the House of Representatives and 97% of the seats in the Senate.

  • I’m genuinely curious what percentage of those non-National and non-Labor seats starting in 1996 were former National or Labor party members. Commented Dec 19, 2023 at 3:15
  • From Wikipedia: 1996 NZ general election: Former National MP Petere Dunne won one electorate seat as United New Zealand, helped by his former party not running a candidate against him. NZ First admitted three MPs from National and Labour. I don't think Alliance admitted any MPs from other parties that election. Corrections welcome! Commented Dec 19, 2023 at 3:27
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    @AustinHemmelgarn: That's a perfectly good Q you could ask on this site. (I don't think though that the comments section here are a good place to discuss that Q.)
    – user103496
    Commented Dec 19, 2023 at 3:41
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    @ChrisBurgess 1) Peter Dunne was a former Labour MP, not a National MP; 2) his former party very much did run a candidate against him; 3) the Wikipedia page says nothing of the sort. Commented Dec 19, 2023 at 4:19
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    @MichaelMacAskill: Thanks for pointing out my error: for 2020, I erroneously swapped the numbers for National and Labour. Now fixed
    – user103496
    Commented Dec 20, 2023 at 3:28

France, though formally a multi-party system, was for about half a century essentially a two-party competition between the socialist party (Parti socialiste) and the right-wing gaullist party RPR-UDF/UMP (nowadays Les Républicains). In 2017 Emmanuel Macron has won the presidential election as a third party candidate with his new movement En Marche. This movement became a prominent political force (as party Renaissance), the socialists faded away, in favor of more extreme La France Insoumise, while the right party was undermined from the extreme right by the Rassemblement National of Marine Le Pen.

It is worth noting that even at the times when the presidential elections were dominated by the two major parties, the smaller parties actively participated in local self-government, and in the legislative bodies at all levels.

Israel is a parliamentary democracy that is inherently multiparty. However, from even before the establishment of the state it had been dominated by historically strong labor/socialist movement (Ben Gurion, Golda Meir, Yitzhak Rabin, Ehud Barack) and the right-wing party nowadays known as Likud (Menahem Begin, Yitzhak Shamir, Ariel Sharon, Benjamin Netanyahu.) In 2006 Ariel Sharon, after losing the party primaries to Netanyahu, but believing in the broad national support for his policy of withdrawal from Gaza and West Bank, split the Likud, founding movement Kadima. After he suffered a stroke, Kadima still became the ruling party under the leadership of Ehud Olmert, but didn't remain a major force for a long time. The labor party also faded away, leaving place to several younger and more dynamic parties.

See List of prime ministers of Israel - Mapai/Alignment/One Israel are the labor party or the alliances built around this party, while Herut/Likud is the traditional right-wing party.)

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    UMP only existed during 13 years. It was called RPR+UDF before. Commented Dec 19, 2023 at 11:38
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    @EricDuminil RPR, UMP, LR, it's always been the same party even though they change their logo more often than Le journal de Mickey; saying that they have "only existed during 13 years" is disingenuous in my opinion.
    – Stef
    Commented Dec 19, 2023 at 12:06
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    @RogerV. I think it's worth mentioning that although the presidential election was dominated by two parties, the other parties were represented at the legislative elections.
    – Stef
    Commented Dec 19, 2023 at 12:07
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    Israel has always had consistent parliamentary representation of multiple parties. IIANM, the two largest parties never exceeded... 80% of the seats, and maybe it's even less.
    – einpoklum
    Commented Dec 19, 2023 at 14:06
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    @RogerV.: Well, in that case, the second half of your answer is not a valid example of a transition to a multi-party system, since Israel was always a multi-party system. (Not downvoting because of the first part of your answer.)
    – einpoklum
    Commented Dec 19, 2023 at 14:29

Québec, although not a country, was basically a two-party state (or province) from about 1976 to 2018. There were more than two parties running, but only two of them were popular enough to gain enough votes to become a government.

The Liberal Party (led by Robert Bourassa from 1970 to 1976 then 1983 to 1994) and the Parti Québécois (led by René Lévesque from 1968 to 1985) would alternate as having the majority of seats at the Assemblée Nationale (parliament): Basically, when electors grew tired of one party, they would elect the other one at the next elections.

This broke in 2018, when the Coalition Avenir Québec, led by François Legault, won a majority of 74 of the 125 seats—they held 22 seats from 2014 to 2018, and 19 from 2012 to 2014, then being a new party (founded in 2011).

So, while not being a strictly two-party system, the “oligarchy” of the two main parties was broken to give way to a third party.

There are other similar examples in Québec’s history and Canada’s history as well.


Australia has long used preferential voting systems at a Federal level and uses various forms of ranked voting for almost all elections, but such preferential voting was only introduced for federal elections in 1918. Between the founding of the Federal Commonwealth in 1901 and the 1919 Federal Election I presume a FPTP system was used, as results from those years do appear to have elected candidates for two parties only.

Why and how was it introduced? From what I remember reading, it was the rise of the Country Party, a party representing small farmers. It began splitting the anti-Labor vote in conservative rural areas. Which permitted progressive Labor candidates to win seats with a minority vote. In response, a conservative federal government introduced preferential voting as a way to permit competition between the two conservative parties without putting seats at risk of going to the other side of politics.

Could this happen in contemporary times in certain other countries? It doesn’t feel impossible.


Perhaps I was too focused on trying to answer the author's question itself while avoiding delving into the specifics and background of two decades of chaotic early-Commonwealth of Australia politics. To elaborate, for anyone interested in details:

The first three Australian federal elections (1901, 1903, 1906) resulted in resulted in a spectacularly unstable multi-party system of minority governments with hung parliaments and uncooperative minor parties. One might not-unfairly dismiss entirely the first decade of Australian politics as "teething pains":

  • As user103496 commented, this was not a two-party system. However, it was also not a functional multi-party system, in the sense that the Westminster parliamentary system ideally forms stable governments that will at least function until the next election.
  • Normally, in multi-party systems, alliances and coalitions see one group or faction gather a mandate to form stable government. This was something that the (mostly) FPTP electoral system of the day permitted, and it was a Westminster parliamentary system which permits minority government.
  • These three elections saw eight Prime Ministers in nine years.
  • In the 1901 election, New South Wales, Victoria, South Australia, Western Australia used First past the post voting systems; Queensland used the Contingent vote system (IRV), Tasmania used the Hare-clark system (STV).
  • Federation was scheduled for 1 January 1901. The first election was scheduled for March 1901. Whoops. So the first Governor General, having arrived from Britain about two weeks prior to Federation, initially tried to appoint as an interim caretaker Prime Minister a politician who had strongly opposed Federation, because precedents.
  • Governments were formed by shifting coalitions which didn't often endure.
  • This chaotic environment saw the world's first socialist or social-democrat party at a national-level (the 1904 Watson government)…
  • …not by election, because Watson's Labour Party had the third largest result with 23 seats, but because Labour withdrew support from Deakin's Protectionist Party (26 seats) and Reid's Free Trade Party (25 seats) declined the position, so the Governor General just ran down the list to Watson…
  • …though he wasn't aware that Watson wasn't even eligible for election to the Parliament because he wasn't a British citizen
  • …and Watson naturally lacked any sort of alliance or coalition to actually get anything passed, and he resigned after only 4 months.
  • But shortly thereafter Labour had their own majority after the 1910 election

So yes, I tend to dismiss the first three elections as just signs of the bizarre political climate where norms hadn't yet quite been established. Yet out of that very unstable era things settled down into a two-party system at the Federal level along a (socialist/anti-socialist spectrum) for over a decade:

  • The Fusion of the Protectionist Party and Anti-Socialist Party set up a two-party system which would have been reassuringly familiar to politicians who largely still identified as British more than Australian.
  • Of the elections in 1910, 1913, 1914, and 1917, seats went almost entirely to the Labour/Labor Party or the conservative party opposing them (Commonwealth Liberal Party and then Nationalist Party).
  • In this decade, only two elections saw a Lower House seat go to others: George Wise won as an independent in 1914, and Frederick Francis as an "independent Nationalist" in 1919. And none at all in the Senate.
  • So this was a very solid, stable 2-party system.
  • Until the rise of the Country Party threatened to split the vote away from the conservative Nationalist party. Farmers' organisations resolved to run candidates of their own in opposition to the Nationalist Party.
  • The seat of Swan in Western Australia had been a Nationalist seat for years, safely held by Sir John Forrest who had won with large proportions of the (FPTP) vote: 60.2% (10.2% margin) in 1910, 54.9% (4.9% margin) in 1913, 59.2% (9.2% margin) in 1914, and run unopposed in 1917. And then passed away from cancer.
  • The Swan by-election in October 1918 after Forrest's death saw a Labour candidate elected with just 34.4% of the vote, after the Nationalist candidate (29.6%) split the vote with the candidate from the Country Party of Western Australia (31.4%).
  • Which was enough for Billy Hughes's political instincts to push for the Commonwealth Electoral Act 1918, which replaced the previous first-past-the-post system used in the House of Representatives with IRV (Instant-Runoff Voting), which is perhaps better known as preferential voting in Australia, ranked-choice voting (RCV) in the US, or Alternative Vote in the UK. The Act was then amended in 1919 to also allow preferential voting for the Senate. (Though it wouldn't be until 1948 that proportional representation (STV) was introduced for the Senate)
  • The Labor Party initially opposed the introduction of preferential voting in this political environment.

So my thesis that is that:

  • the first years of Australian national politics after Federation were amazingly wild and should be entirely disregarded as outliers
  • Australia then settled into a comfortable and stable two-party Federal system
  • threatening a political party with political purgatory by demonstrably splitting their vote and threatening to consign them to imminent political purgatory, has worked in Australia to motivate them to pass legislation to ditch FPTP electoral systems for more representative systems (though not the most representative system)
  • But the Country Party had to be entirely ready to follow through and seize votes for themselves

Probably beyond the scope of the question (and my answer):

  • the degree of popular support for more representative voting systems
  • use of preferential and/or proportional representation in Australia at a State level which exposed voters to such systems
  • the importance of Compulsory Voting, later introduced by the Commonwealth Electoral Act 1924
  • the sometimes extreme diversity of minority parties elected to The Australian Senate under STV
  • the role of the Australian Democrats
  • the role of the Australian Greens
  • the impacts on, or results of, later elections involving such third/fourth or more minor parties
  • while Australia still has a political landscape of essentially two main factions, the requirement for parliamentary coalition, and the possibility of minority parties being required for support in a hung parliament, has resulted in a more diverse political environment than simply two parties would permit
  • Your answer could be improved with additional supporting information. Please edit to add further details, such as citations or documentation, so that others can confirm that your answer is correct. You can find more information on how to write good answers in the help center.
    – Community Bot
    Commented Dec 20, 2023 at 18:22
  • Would also be improved with info about the formation of the 'Keep the bastards honest' Democrats in the 70s who had balance of power for a number of years..
    – mcalex
    Commented Dec 21, 2023 at 2:47
  • Seats won by top 2 parties: 1901: Top 2 parties won 57/75 (House, 76%) 27/36 (Senate, 75%) // 1903: 48/75 (64%), 20/36 (55.5%) // 1906: 52/75 (69.3%), 32/36 (89%) // This was not a two-party system
    – user103496
    Commented Dec 21, 2023 at 5:03

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