In the United States we have the two-party system unlike many other nations, including Britain, Germany, Israel, and many others. Multiple parties ultimately results in forced cooperation between multiple parties in order to create a coalition to govern.

  • Why do we have only two parties in the US government?

  • What are the advantages of a two-party system over a multiparty system?

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    It is unclear what you are asking. I attempted to clarify what you wrote, but it is unclear if you want an answer to the former/latter bullet-point.
    – user1873
    Nov 10, 2013 at 9:26
  • Well if my question wasn't gutted it would have been more clear what I was asking. The fact is that we have a two party system that is broken and while other multi party systems are not necessarily better, I don't understand why we are so insistent on keeping this two party broken system? What could possibly be the advantage of it that is worth all the shortcomings and chaotic mess that it comes with? Why not include the independent, green, labor, whatever parties included rather than just flush the votes they get because its not D or R. Nov 11, 2013 at 2:31
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    as the answer below points out, we aren't keeping a two party system, it just ends up that way as a natural outcome of first-past-the-post. Are you asking why don't we change how we elect people and use a different system other than FPTP? There is a green, independent, and labor in the US. What question were you looking to ask that the above doesn't answer?
    – user1873
    Nov 11, 2013 at 2:46
  • Actually it is not a matter of how it works out, anyone running as anything other than D or R is not even considered, how is that a natural outcome? Its intentional. Nov 11, 2013 at 2:51
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    @GµårÐïåñ - It's quite possibly intentional by the parties in charge, but not inherent in the system.
    – Bobson
    Nov 11, 2013 at 3:59

5 Answers 5


As Michael WS points out, a 'first past the post' system (which the US has) encourages a two party system. However many other countries also run a 'first past the post' system without such a strong two-party emphasis. The UK and Canada are two examples where first-past-the-post allows for multiple parties in the legislature. The US has a few other systems which make two-parties even more likely.

The Presidential System. Giving substantial power to a president who is directly elected (more or less) encourages two parties. There is virtually no chance that a third party could capture the presidency, and even running as a third party disadvantages the candidate who is closest to your views, making it more likely that the person you least agree with is elected. Note that the presidential election is first-past-the-post at two levels - you have to be a majority at the state level to get on the scoreboard (in most states), and then get a majority of votes in the electoral college.

The Staggered Senate Elections The fact that each state elects only one senator at a time means its an all-or-nothing proposition. All the same reasons for not running a third candidate for president apply almost as much to the Senate.

The Primary System It is at least conceivable that there are House districts where a majority of voters would vote for a Libertarian Party, or a Green party candidate, or some other non-mainstream party, over a typical Republican or Democrat. Such things happen in other countries. However for candidates with those beliefs, the primary system ensures that rather than stand as a 'Libertarian party' or 'Green party' candidate it is better to attach yourself to one of the big two parties, stand in a primary and become their candidate. This gets you access to the fundraising and campaigning organization of the big party. (The lack of effective limits on campaign spends also makes this a more attractive approach than it might in other countries) And if your policies are popular with the electorate then the party will probably approve you.

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    Personally, I blame the primary system the most myself. By winnowing the field down to a single candidate per party, it makes it that much harder for anyone else to get a foot in the door. If everyone ran against each other, it would allow for much more vote-spreading. It's also the most recent addition to the system - some time in the 70's.
    – Bobson
    Nov 13, 2013 at 21:45
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    Regarding the UK, it depends a bit what you mean. Medium sized national parties may exist in a suppressed form and small national parties sometimes get a seat. But winning a seat typically require 3-10 times as many votes as for the largest two parties. This means that national party number 3 and onwards do not get many seats and are most likely to be excluded from the government side of the legislature. It could be called political suppression. Exceptions are parties where supporters are concentrated in a part of the country, for instance the Scottish SNP, but that is how FPTP works.
    – nsandersen
    May 30, 2019 at 17:36

The two party system is reflective of our system of voting. Major parties have no incentive to change this. The advantage of keeping the system is for those with power stay in power.

The two party system in the US is not by design. It has been hypothesized that plurality voting (first past the post) devolves into two party systems.3 This is called Duverger's Law after the French sociologist Maurice Duverger.

Here is a description from wikipedia:

Duverger's law suggests a nexus or synthesis between a party system and an electoral system: a proportional representation (PR) system creates the electoral conditions necessary to foster party development while a plurality system marginalizes many smaller political parties, resulting in what is known as a two-party system.

This video gives a brief description of the problems with First Past The Post Voting

  • Thank you, I took a look at what you provided, very educational. However, what I observe as a citizen is that in fact and in practice if you don't vote democrat or republican, your vote means NOTHING. Not that voting for the other two your vote means anything either but anything besides them its means even less than nothing, its is IGNORED. The fact is that an Independent will NEVER become anything even if they manage to get 80% of the vote, simply because they are not one of the two parties. Why? I mean why are we so hell bent on forcing TWO parties and nothing else. Nov 11, 2013 at 2:43
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    yes, but national elections are a bit harder. Both originally ran in Democratic primaries and caucus with Democrats. I am not sure if that is the same as a true independent challenger on a national election
    – Michael WS
    Nov 11, 2013 at 5:09
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    "The two party system is reflective of our system of voting." The UK also uses first-past-the-post, yet it has 3 (or 2.5) major parties. In the US, might gerrymandering and funding have something to do with it? Nov 11, 2013 at 11:38
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    You are right. Gerrymandering is part of the issue as is the current electoral college structure. Currently in the us, third parties cannot even debate.
    – Michael WS
    Nov 11, 2013 at 13:59
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    @MichaelWS - If you even can call them "debates". More like "Talking point rehashes"
    – Bobson
    Nov 11, 2013 at 17:17

There are some advantages, when compared to extreme cases in the multi-party spectrum.

For example, Israel has had 2 elections and still hasn't managed to choose a PM because no stable coalition has been possible so far between parties that dislike each other. For a while, Italy's PMs averaged 1.5-2 years in their job.

Multi party systems, depending on the circumstances, can also degenerate into horse trading, government pork and kingmakers parties. This is when a small party is needed to give the governing party a parliamentary majority. In that case, a small party can sometimes exert outsize influence on policy by insisting on particular treatment of something, even when the majority of voters are not sympathetic.

In BC, we've recently had our 2, or 3rd, referendum about moving away from first past the post voting. Guess what? Despite a whole lot of online claims of their moral superiority by people fond of proportional representation, the referendum came out more than 60% in favor of keeping things as they were.

Note also that the US isn't quite as much an outlier as all that: France for example pretty always elects presidents from either the center left Socialists or the center right party (Macron being an exception). Canadian elections generally either get a Liberal or whatever the center right conservative party calls itself, although minority governments do happen. UK elections: Labour or Conservatives. So, in practice, these countries don't have that much variability in their core parties.

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    Actually, in the Israeli example, the inability to form a coalition is not inherently a feature of a many-party system, but rather of the personal circumstances of the leader of one of the two larger party. In fact, had Israel really been an "extremely" multi-party state, such individual issues could have been worked around, since no party was indispensible for coalitions, even of its ideological surroundings.
    – einpoklum
    Dec 10, 2019 at 21:28
  • @einpoklum I'm a big fan of PR, but Belgium, The Netherlands, and Sweden (among others) have also had problems forming (majority) coalitions, and after a majority in Germany voted for parties who wanted to abolish parliamentary democracy in the 1930s (communists on one side, nazis on the other) democracy broke down completely (which is one of the reasons post-war Germany has a 5% threshold to enter parliament in the first place).
    – gerrit
    Nov 4, 2020 at 12:34
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    @gerrit: 1. I didn't say that problems forming a government are extremely rare, I said they were not inherent in a multi-party system. 2. In Israel, there has rarely been a problem forming a coalition government on the national level. The municipal elections here are also multi-party, and even with often no party having even 20% of the vote, coalitions form well enough. 3. I would guess coalition forming in NL, Germany and Sweden isn't usually so hard 4. I don't think you can make a serious argument that a low threshold of entry into parliament is a significant cause for the rise of Nazism.
    – einpoklum
    Nov 4, 2020 at 13:03
  • 5. I personally don't support parliamentary democracy myself (I'm an Anarchist), I was just making an observation.
    – einpoklum
    Nov 4, 2020 at 13:05
  • re (3): coalitions are always easier locally — re (4): almost nothing in politics is monocausal, but I will argue that the very large number of tiny parties did significantly contribute to the fragmentation and the political crisis in the Weimar Republic, which aided the rise of nazism (only 5 of 15 parties entering Parliament in 1930 would have done so with a 5% threshold, and from what I remember in history class, this was one of the reasons Germany has this threshold since WW II).
    – gerrit
    Nov 4, 2020 at 13:33

Two parties in the poilitical system creates a duopoly... which if it were in any other part of the economy, the government would be trying to get it broken up as it being too close to a monopoly.

The result of a dupoly is more clear than ever -- both parties are becoming more and more extreme. It will only get worse before it fixes itself up.


Practical feasibility in a pre-industrial society

This is it. This is the reason why the US and England have this kind of system. Simply because it is practically feasible in the constraints of a pre-industrial society, where messages have to be relayed by horse or at best a telegraph line.

What benefits does it have now? Well, as bert2000's answer points out, its very suited to keep these two major factions in power and stabilizes the system as a duopoly, which is neat for those two parties, because they can largely ignore any opposition other than each other. What good it does for the people? Who knows, they don't have a choice anymore

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