I live in Germany, and it seems completely strange to see a stable separation between Republicans and Democrats, and even somewhat near half of the votes for each.

I see that the number of two parties is based on the method of voting. But is that the complete reason? Here, there are separate parties that potentially need to build a coalition to reach 50% or more of the votes.

The parties can have a small number of votes, down to 5%, but there are two large parties that are somewhat similar in terms of the separation between Republicans and Democrats. If none of them get 50% of votes, they need to accept to include one or more other parties into the government, and sometimes it's even the two largest parties.

The last case would be similar to Republicans and Democrats building a government together. Currently, both parties are relevant as some component of the government - but in a different way.

Basically, the hard separation - so hard I would even call it a front, feels somewhat strange. Why does it exist?

  • 2
    Many of the answers are pre-occupied with the American federal government; as these two parties are dominant at the state and municipal levels as well, which I personally find far more perplexing, I would appreciate an answer that addresses this phenomenon also.
    – Roger
    Commented Nov 20, 2019 at 15:25
  • What's not mentioned in the answers is also that a large part of our population seems to be out of their minds, brainwashed, stupid, gullible, or whatever. This leads to extreme polarization and support of people, groups, policies, etc. that no normal person would support. Sometimes it's out of desperation, fear, or anger as well, rather than calm and collected thinking. Combine this with lots of groupthink, echo chambers, and tribalism, and then our current political situation makes complete sense...
    – Andrew
    Commented Nov 21, 2019 at 15:59
  • I'll also add that proper information dissemination and control, trust in one source of information vs. another, fake media/news articles and ads, etc. are a huge problem. If it's not already a major problem for you, I suggest you be vigilant to prepare for it, because it's coming. And when I say "you", I mean everyone in your country. Protect yourselves from disinformation, establish and support reliable sources of information.
    – Andrew
    Commented Nov 21, 2019 at 16:02
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    @Andrew That is a very interesting aspect, well worth an answer, so that it does not get lost in the comments. Commented Nov 21, 2019 at 23:56
  • My first comment talks badly about people, and isn't "sourced", so it probably wouldn't be well-received as an answer. My second comment was moreso a direct message to you and people wondering about this as you do, not really answering the question.
    – Andrew
    Commented Nov 22, 2019 at 19:08

10 Answers 10


The answer is First Past The Post. The nature of the voting system is such that many people who would rather support a 3rd Party feel compelled to vote against the party that they like the least, rather than for the party they support the most, because their preferred candidate is unlikely to win the race anyway and thus they are simply removing support from whichever of the two main party's candidates that they hate the least. This means support gravitates towards the two parties that are seen as being most likely to win the election overall.

In Germany you use MMR which, in addition to a FPTP element, also introduces a proportional representation element that means smaller parties are also often elected (since there's no reason not to vote for your actual preference under proportional representation).

There are other factors. As @RayButterworth handily points out, nationalist sentiment can create strong blocs such as the Scottish National Party in the United Kingdom or Bloc Québécois in Canada - parties which are strongly focused on regional autonomy or even secessionism. The US lacks such sentiment in any great amount these days (probably an artifact of the nation's history so far) which means there's not that party drawing off support.

As @CoedRhyfelwr points out there's also the US constitutional arrangements to consider. Unlike in a parliamentary democracy, where election of a legislature is also the election of a government in proxy, the US system of directly electing the executive branch means that parties do not need to enter into coalitions to govern; there is after all only one President. That being the case, they possibly feel less inclined to compromise with one another.

Tl;dr yes, it's mostly because of the voting methods, but there's some history and constitutional structural reasons too.


American political parties are essentially standing coalitions that do their coalition building before elections instead of after

What is typical in Europe and other parts of the world is for a collection of smaller parties to win to varying degrees in elections, and after the elections are over, form the whatever coalition is necessary to govern.

Here in America, there are already two major parties, and they are typically very good at competing with each other to win elections. As such, third parties typically do not last long, because any third party that starts to become popular is viewed as evidence of an underserved group who could be voting for a major party instead. Thus, there is active effort to prevent third parties from forming by bringing those voters into the governing coalitions of the major parties. The result is that the coalitions are built before the election, not afterwards, and are essentially always standing.

This is plain to see when looking at the interest groups that make up the two major parties. There is very little reason why socially conservative, highly religious people would be in the same party as people who prefer free market economics, or aggressive foreign policy, yet those are three of the groups that (used to) form the Republican Party. There's no logical reason why environmentalists, ethnic minorities, and proponents of gun control would all be in a party together, except they make up parts of the Democratic Party's coalition. The make up of the parties is largely the result of transactional interactions to create winning coalitions in advance of an election.

FPTP is not sufficient to explain this uniquely American behavior

Many answers mention "first past the post" voting as being the cause of this uniquely American behavior. FPTP is in use in many countries, even in parliamentary countries that undergo parliamentary coalition building like the UK and Canada. Although FPTP probably contributes to it, it is not sufficient to explain it.

What is unique to America is that there are many efforts at the state level to limit the ability of third parties to gain ballot access, largely in the form of laws that assume the winner of any given election will be either a Democrat or a Republican. Largely because those laws were written by Democrats and Republicans, in one of the cases where Democrats and Republicans have worked very well together for many decades.


Duverger's law or principle says that plurality rule elections (e.g. first past the post) in single member districts tend to result in two-party systems, while multi-member districts and/or proportional representation tend to result in multi-party systems.

Under FPTP, people will tend not to vote for the perceived weakest parties because they have no chance of winning (of course a self-fulfilling prophecy) and parties that consistently come second in the popular vote will win no electoral votes or seats in the legislature regardless of a significant share of the popular vote.

The government will tend to be formed by one of the two main parties.

The UK is another example, albeit not as extreme as the USA - particularly in recent elections. However, geographically concentrated parties, e.g. the Scottish National Party, can distort the results - in the House of Commons, the Scottish Conservative vote tends to be under-represented but the Conservative UK-wide vote over-represented. Infamously, in 2015's general election UKIP won more votes than the Liberal Democrats and SNP combined, but only won one seat while the Lib Dems won eight and the SNP 56.

In contrast, in Germany and some other European countries the share of seats in the legislature is approximately proportional to the share of the vote, with distortions depending on the pecularities of the systems and the contemporaneous circumstances.

I would add that, as an outside observer, in my limited experience I have found the US broadcast news more tribal or polarised than UK broadcast news (I do not know about other European broadcast news). Indeed, in the UK, broadcast news is regulated and it must be "reported with due accuracy and presented with due impartiality".

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    As a Brit, I'd like to add that while our broadcast news is regulated and impartial, our newspapers are just as "tribal and polarised" as US broadcast news.
    – F1Krazy
    Commented Nov 18, 2019 at 11:52
  • @F1Krazy I am inclined to agree with you about that.
    – Lag
    Commented Nov 18, 2019 at 12:10
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    @F1Krazy and Lag: concerning the impartiality, my first reaction was "That's not how it looks to me!" However, I must admit that it is nearly impossible to remove all impartiality from reporting, as simply the decisions about what you decide to report on can make the picture of the world that you paint to be partial no matter what you say about it.
    – Aaron
    Commented Nov 18, 2019 at 19:43
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    The whole point of Duverger's law is that there being at most 2 parties that have a reasonable chance of winning a FPTP election is not a "self-fulfilling prophecy", but a mathematical fact.
    – T.E.D.
    Commented Nov 18, 2019 at 21:08
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    @gerrit - Take a look at that historical graph. What I see there is district that has historically been a one or two party district, but has been undergoing a party realignment since about 2005. 12-18 years is not out of line with how long that process has been known to take in the US.
    – T.E.D.
    Commented Nov 19, 2019 at 17:16

A critical piece of the puzzle is how the executive branch is elected. While there is more to government that the executive, for many people, this is where their principal understanding of party politics comes from.

The 12th Amendment of the US Constitution (which governs this process) says:

The person having the greatest number of votes for President, shall be the President, if such number be a majority of the whole number of Electors appointed; and if no person have such majority, then from the persons having the highest numbers not exceeding three on the list of those voted for as President, the House of Representatives shall choose immediately, by ballot, the President.

This means that, in order to be elected President, a candidate needs to have over half of the electoral college votes. If no candidate has this, then the legislative branch will choose.

This means that it is incredibly difficult for a new party to hold power in the executive branch. Adding a viable third candidate would, most likely, split the vote such that no candidate gained the majority. Therefore, it would fall to the legislative branch, which would probably vote along party lines.

So, to get a third-party president, that party would need to have significant sway in the legislative branch. But, getting that without a third-party president to bolster their reputation, is going to be hard.

So, there's a chicken and egg problem. The US is doomed to have just 2 parties until they undergo electoral reform to change how they elect their executive branch.

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    Historically, 3rd party presidential candidates do not cause the election to fall to the House of Representatives (it has happened, but not in a long time). A strong 3rd party candidate more often serves as a spoiler for whichever candidate whose position most closely aligns with their 3rd party. For an egregious example, look at the 1912 presidential election: Roosevelt ran as a 3rd party candidate after failing to win the Republican nomination, and received more votes than the incumbent Taft (R), resulting in a win for Wilson (D), who received fewer votes than Roosevelt and Taft combined.
    – asgallant
    Commented Nov 18, 2019 at 22:20
  • @asgallant that's very fair comment. I intended to imply, by "viable", a candidate that could potentially win, but you're right. Most 3rd party candidates are little more than spoilers
    – Dancrumb
    Commented Nov 19, 2019 at 15:51
  • but, more generally, whether it's because they are a spoiler for a single candidate or because of the way the constitution lays things out, a 3rd party candidate has close to zero chance of being elected president until they have a strong foothold in Congress.
    – Dancrumb
    Commented Nov 19, 2019 at 15:52

Barriers to entry

Especially at the state levels—where most political hopefuls would start their ascent to notability before any transition to federal positions—the Democrats and Republicans both benefit from and exploit a series of laws that deter and impede third parties disproportionately to their own.

Here's an article that covers some examples of this, such as:

  • Texas requires candidates to file paperwork for the election more than a year before the election itself will actually take place. This is relatively easy for the existing major parties, with their extensive internal bureaucracies and resources, as well as familiarity with the process. But is burdensome to third party candidates, both because of the greater difficulty of filing that paperwork as well as the fact that would-be independent candidates may be inspired by more recent controversies, which may not happen until after the deadline.
  • Arizona lets you get on the ballot by collecting signatures. You need 6000 if you're a Democrat or Republican, but you need 37,000 (and with the likelihood some signatures may be disputed, duplicated, not from valid voters, etc., that's more like 50,000 in practice) otherwise. That's a sizable disparity that clearly favors the established duo.
  • Many states have "sore loser" laws. These prevent someone who ran in a major party's primary and lost from then registering as an independent or third party and running as such in the real election. Proponents say this makes sure the party effectively doesn't undercut itself and deny the will of the people, because the "sore loser" is likely to just split the vote between the two candidates, letting the single candidate from the other main party win easily (even in a region where they are otherwise a notable minority). But the curious reality of primaries is that they are dictated heavily by the more activist oriented part of the base (for either of the two major parties). They are often poor reflections of the broader, "truer" interests of the greater electorate. As such more polarizing nominees can more easily win the primaries, while the more moderate candidate that could probably attract more votes in the actual election is left out. This leads to progressive polarization of government and legislatures, and distorts and averts the will and interests of the people.

The first two points are examples of barriers to ballot access.

A point not mentioned is the difficulty of participating in televised political debates, especially Presidential ones. Independent and third party candidates may effectively be barred entirely, or have to demonstrate sizable support and resources; and getting those after the debate is usually the goal for the independent and third party candidate. They need a stronger public perception, which a good debate performance can provide, but they are barred from the outset, while the Democrat and Republican candidates simply slide in on the coattails of the party's name recognition.


One reason is that both parties are "Big Tent" and the nearest two contenders for third party in the modern election system (Libertarian Party and Green Party, as the 3rd largest and 4th largest respectively) generally can find enough common ground with a political faction within in one of the two parties (Most moderate Republicans are Libertarian, which in the States is synonymous with being classical liberal minarchists as opposed to the more anarchist Libertarians in Europe, and the Green Party tends to find common ground with far-left Democratic parties.).

It's not that coalitions exist, but it takes place in intra-party politics rather than inter-party politics like in Germany. Additionally, American Political parties are not as tightly restrictive on their members votes in Congress as many European politics. If the Democratic party is opposed to a bill before congress, they will generally have a published opinion... but that doesn't stop an elected democrat from voting against their party for a number of reasons (mostly job security... if you're in a district that is prone to being a swing district, you're more prone to crossing the asile as that middle/centrist/moderate wing isn't something to sneak at. Typically the middle ground is very unpredictable and easy to flip and if you won on narrow margins, you tend to not be a permanent fixture on Capital Hill to begin with.

Despite Gerrymandering being a thing in the U.S., all but seven states are subdivided into single member districts (those 7 only have one representative, so they aren't divided) and the lower house, which is historically the more politically unstable of the two houses (by design, by the way), and members of either party are more on the hook for their political agendas when they are opposed to local political agendas. If the local economy is a fishing industry, if their representative backs an environmental bill that costs the fishing industry as a result, that representative might not get reelected. And Representatives get re-elected every two years. The Upper House tends to be more stable as terms are for 6 years with one third being re-elected every two years. While the Red/Blue/Swing state phenomena is widely known, if you look at any U.S. map of national elections breaking down by either county or congressional district, you'll see most "solid color states" aren't that solid in color at the lower levels. California, Texas, and Florida are the three largest states by population AND are each the largest Blue (Democrat), Red (Republican), and Swing states (respectively) in the nation. Looking at these state, at a district level, you'll see plenty of districts held by the un-favored party. And while this tends to follow Urban-Rural divide, Florida gets a check as the state is very much Republican except for the more densely packed and strongly favors Democrats to the point that the state is competitive (it's so close that on more than one occasion, Florida has gone to recount to ensure that they counted the number properly). It's not helped that even in reliably democrat controlled Miami, the Cuban Vote is generally pro-Republican (the Republican Party tends to take a stronger stance against Castro-Cuba than the Democrats... and when you're fleeing because of Castro, that's a vote getter).

So since both parties will often have many members that have to be more moderate than the party's typical base. In fact, it's often the party in the majority that has a more difficult time getting what they want done than the minority party, since it's a lot easier to agree on a negative than it is on a positive. The minority party doesn't have to be unified as to what part of a bill is preventing them for saying new, but all parts have to agree for the majority. And typically, the members of the majority are more likely to cross the aisle than the minority because of this fact.

As a final note, as I'm not sure about German's use of political terminology, but in the United States, the leader of the majority in the lower house is not "the government" as it would be called in the UK English. Americans typically use "administration" to mean the same thing the British refer to as "government". Government to an American English speaker typically means all three branches (Legislative, Executive, and Judicial) and not "the policies of the current idiot in charge". In the U.S. the President of the United States and his "administration" typically forms policy with in the confines of laws passed Congress. This is different from Germany where the President of Germany is usually a more cerimonial post while the Chancellor, the leader of the largest party in the majority coalition has much more political power and makes the policy to the execution of laws. The U.S. Speaker of the House is leadership with in the House and may be writing laws for a President who is not of the Speaker's party. This is, in the U.S., typically called divided government and generally denotes a situation where the two houses of congress (the senate and house of representatives) and the Presidency are not all held by one political party. In fact, for the current decade (2010-2020) there have only been three years where all three political bodies have been controlled by the same party in majority (2011 ended Democrat control of the House, 2016-2018 saw Republicans gain the White House, having reclaimed the Senate two years previously. Keep in mind that votes are held in November while the change of office typically occurs in January, with the House and Senate beginning shortly after New Years Day and the Presidency being on January 20th.)

  • In your first sentence do you mean "generally can't" instead of "generally can"?
    – Lag
    Commented Nov 18, 2019 at 17:33
  • 2
    @Lag The wording is difficult to follow, but I think hszmv did mean can. As in, "The green party can find a lot in common with the democrats, so a lot of its people will just support the democrats."
    – Aaron
    Commented Nov 18, 2019 at 19:48

At the risk of coming across as naïve, I will say that the reason is that the two political parties are extremely good at finding out what American voters want (on average), in order to win elections. Democrats approach the mean from the left; Republicans approach it from the right. As others here observe, presidential elections are almost always very close. The difference between Republican and Democratic victory is almost always a result of finding a way to appear more attractive on some centrist issue.

Obviously, there is rhetorical value in painting your political opponents as extremists. But substantive change to American society is almost never on the table in American elections.

The other answers offer good insight into what “left” and “right” mean in America: in our politics, coalition building happens before elections.

(And as a mild expression of patriotism, I can't help observing that in multiparty systems, you nevertheless tend to end up with two coalitions! This seems inherent in the requirement to vote “yes” or “no” on particular pieces of legislation.)


My novice understanding of the US political situation is this:

Statistically, one third of the population leans left of the current spectrum, one third centrist/moderate, one third right. The spectrum moves over time, so what's left today might be right tomorrow, but the split will move with it over time as well.

Since any first-past-the-post system devolves to two parties, as in a 34/33/33 percent split the party with 34% would win as if it was 100/0/0, voters will decide on the lesser of two evils, not the best option. This means that the 33% left-leaning voters will always vote democrats, 33% will vote republican and the 33% centrists will tend to be roughly evenly split among both with some variation depending on the candidates.

Since the centrists will then be in the minority in their respective parties, being outnumbered by the hard(er)-left/right, it results in a political situation where it's difficult to find a middle ground.

  • 1
    "Since any first-past-the-post system devolves to two parties": it tends to devolve; it's not inevitable. In any case, it might be worth mentioning Duverger's law. Commented Nov 18, 2019 at 11:26
  • 1
    Do you have a citation for left-center-right being 1/3rd each? Commented Nov 18, 2019 at 19:53
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    @user3067860 The answer mentioned the spectrum moving around (i.e. being relative rather than absolute), so it's pretty much by definition: the left-most third will alway be a third of the population, as will the right-most third and the third in the middle.
    – manveti
    Commented Nov 18, 2019 at 20:10
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    @manveti It just seems like a weird definition, since I expect the population would tend towards either a normal distribution or maybe some kind of bimodal/polymodal distribution. Commented Nov 18, 2019 at 20:52
  • 1
    @user3067860: That entirely depends on the arbitrary x-axis you're using. More fundamentally, you appear to assume an interval scale. But in reality, there's no objective "0.10 steps to the right". There's at best "more to the right" and "more to the left".
    – MSalters
    Commented Nov 19, 2019 at 14:01

The Democratic and Republican parties do effectively contain coalitions. The FPTP system forces them to join forces outside the electoral system, before the election.

Example "parties"


  • Service workers
  • African Americans
  • Mexican Americans
  • Social Justice People
  • LGBT
  • Non-Christians


  • Business owners
  • Resource workers (coal, oil, etc.)
  • Hardcore Christians
  • Southerners
  • Cubans who hate Castro

The coalitions do occasionally change In the 1970s, Southerners left the Democratic Party to join the Republican party after the Democratic party began to attune to African American voters.

Sometimes the Resource workers go against each other: a Coal Worker may oppose a Republican who overly favors Natural Gas, a competing industry but both would tend to oppose the Democrats who tend to favor Renewable Energy.


I suppose I shouldn't be surprised that there is no mention of race in the answers so far.

Most of the answers above have provided important pieces of the puzzle, but there can be no understanding of US politics without reference to race, and by extension, slavery. Even gender hasn't divided Americans over the long term as much as race and racism have.

The defining event of the 19th century in the United States was the Civil War. The question of whether to maintain or abolish race-based slavery was, despite foolish apologetics to the contrary, the single issue that brought about that war. In similar fashion, the divide that exists between the current Republican and Democratic parties was defined during the civil rights era, when Republicans insisted on maintaining race-based policies and Democrats voted to abolish them. That era saw a reshuffling and redefinition of party platforms. Without space to go into a lot of detail, long-time Democrats changed parties based on the issue of race. The Republican party became one defined by its racism.

All the arguments about voting methods and barriers to third parties still hold. But nothing divides Americans like race.

  • 1
    Please try to include some references to support historic facts. Many users and visitors may not be familiar with US history.
    – JJJ
    Commented Nov 19, 2019 at 17:15
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    The Civil Rights Act of 1964 was passed with greater Republican support than Democratic support. There were four major votes involved in the passage of the law. Republican support was 80% to 82% in each vote, while Democratic support ranged from 61% to 69%. Opposition was concentrated in the former Confederate states, whose Congressional representation was predominantly Democratic.
    – EvilSnack
    Commented Nov 20, 2019 at 4:08
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    @EvilSnack Yup. Martin Luther King Jr was a Republican for a reason. It wasn't until the "Southern Stategy" after the Civil Rights era that the South became largely Republican. It's also worth pointing out that they were the anti-Slavery party, and it was the election of the first Republican President, Abraham Lincoln, that was one of the main triggers for the Civil War.
    – nick012000
    Commented Nov 20, 2019 at 9:23
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    Actually, it was the other way around. Lincoln was a Republican. This is why so many southern states had Democrat local and state governments up through the 1970's... used to be called Dixiecrats. Some time in the early 1900's, the parties essentially swapped ideologies, but that was slow in filtering down to state politics.
    – tj1000
    Commented Nov 20, 2019 at 14:34

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