I am from India and whenever we hear about US politics and the US Senate, we always hear about two political parties, Democrats and Republicans. So are these the only two political parties in US? Is the US a dual-party system? And is there a Left-wing or Communist party in the US?

  • You should break off the question about a Communist party into a new question. Otherwise, there are multiple questions in here. Commented Apr 11, 2017 at 16:10
  • My main question was about party system. Communist party is just a add-on as US in past has been very anti-communist in their actions Commented Apr 11, 2017 at 16:31
  • China has a one party system, U.S has a two party system. And democracies in the rest of the world have multiparty systems. Commented Apr 11, 2017 at 16:33
  • @dan-klasson some democracies. A table of en.wikipedia.org/wiki/Effective_number_of_parties values at tcd.ie/Political_Science/staff/michael_gallagher/ElSystems/… shows values ranging between 2 and 10 (for Belgium). Admittedly not all of the 2 party systems will have the two parties baked into election law, as has now happened in some parts of the US.
    – origimbo
    Commented Apr 11, 2017 at 17:07
  • 1
    Depends on your definition of "party." One could argue that each Senator is a party, as each of them has his/her own staff and his/her own reelection campaign. And for major proposals they have to be convinced one by one. They work together as the Democratic Coalition and the Republic Coalition.
    – Sjoerd
    Commented Apr 12, 2017 at 20:24

3 Answers 3


The US is effectively a two party system. While other parties do certainly exist - for example, Jill Stein of the Green Party and Gary Johnson of the Liberterian party were candidates in both the 2012 and 2016 Presidential elections - it is rare, though not completely unheard of (for example, Senator Bernie Sanders is technically an Independent who aligns with the Democrats for procedural reasons), for anyone not representing the two main parties to win public office. This happens largely because the US uses first past the post voting extensively, and is entrenched by the high-profile Presidential election being inherently winner take all. You might want to read this previous answer for a more in depth discussion of how this happens.

However, one notable effect of this, compared to countries like my native Australia, is a lot more voter participation within each party. Candidate preselection via the Primary system provides a very public contest of ideas. Possibly because of this, there is also quite a lot more variance and public disagreement between elected representatives, even from the same party. You might consider these to form a 'mini' multi-party system, although some people do also argue the opposite - that the primary system further entrenches two-party dominance.

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    It should be noted that smaller parties are more successful in local elections as opposed to the largely two party dominated federal election. Commented Apr 11, 2017 at 16:29
  • So in the Presidential election there are mostly two parties only and a multi-party like system is present and exercised when Presidential candidates are "elected"?? Commented Apr 11, 2017 at 16:30
  • You forgot to mention the other huge political power in America: Vermin Supreme :). Commented Apr 11, 2017 at 16:38
  • The primary system is not that public though. In many states, independents are not allowed to participate, only party members may participate, and sometimes not even newer party members may participate, you must be a party member for several months. Every state has different rules about this too, but the standard is generally that only long-time Democrats and Republicans may participate in only their own party primaries, and everyone else must sit out the primary process and wait for the two major partys' members to decide for them what their options will be in the general election.
    – J Doe
    Commented Apr 11, 2017 at 18:44
  • @JDoe - Primaries are "public" in the sense that members of a party get to vote to select their candidates. In other countries, this is sometimes not the case (for example, closed list systems). Commented Apr 13, 2017 at 4:31

There are tons of parties in US politics. However, there are two 'big tent' parties that people fall behind during federal elections. Those being the aformentioned Democrats and Republicans.

There are tons of different parties that are free to operate within the United States. From Communist, to Libertarian (our nations third largest party), all the way to far right groups.


As shown in the other answers, the US is de facto a system where two parties dominate the political scene, and has been for a quite a while. While other parties exist (libertarian, greens, socialist, ...), they usually have a very low representation in chambers.

Dual party systems are usually favored by a system where representatives are chosen with the majority of votes on one geographical area. Indeed, one usually needs to get a huge support in order to get the majority of the votes in a single area (most of the time, 1 seat). Proportional representation on the opposite favors the emergence of many smaller parties, since you can get a good representation without a support close to the majority.

A good illustration of this is given by french legislative elections before and after a change from a proportional representation (IVth republic) to a single winner representation (Vth republic). In 1956, with proportionnal representation, much more parties were allocated a significant number of seats than in 1958, with a majoritarian representation by eletoral areas. You can also usually spot the difference between the French first rounds of presidential elections, and the repartition of seats in the parliament.

There are many other countries which combine proportional and majoritarian representation, for which you can spot the differences in the results.

  • First past the post means elections are won by plurality, not majority. A candidate can win with less than a majority as long as they won more votes than anyone else, and they often do win this way.
    – J Doe
    Commented Apr 11, 2017 at 18:48
  • @J DOE good point, the example of the french legislative election is actually a 2 round election, where one needs the majority of expressed votes. I am not sure it is often done in a "first past the post " way, I will try to clarify the answer when I have some time. Commented Apr 11, 2017 at 19:17

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