Why did all countries converge on the exact same rules for voting (no poll tax, full suffrage, no maximum age, etc)?

Question

There are ~190 countries out there and almost all of them have elections of some sort. However it seems like all of them have converged on certain criteria for voters:

• Full suffrage, even in Saudi Arabia
• No poll taxes or other financial criteria for participation, such as being a net tax payer
• No maximum age for voters
• No literacy tests for voting

Everyone converged on a simple "if you're 18-20+ and a citizen, you may come and vote". Why is this the case? Shouldn't there be at least some variation in voting eligibility, especially given how many dictatorships out there exist that don't care about human rights?

Answer 1

First, the premise is not entirely true. To start with, it gives the example of Saudi Arabia, but Saudi Arabia only allows voting in municipal elections, while the national government is a hereditary absolute monarchy.

While "full" suffrage is ultimately more subjective and culture-bound than it might originally seem (Should children be able to vote? Prisoners? Chimpanzees and dolphins? Foreigners? Corporations? AIs? People with severe dementia or other major mental disabilities?), there are certainly countries that lack full suffrage by the standards of most other countries, even ignoring the hereditary absolute monarchies:

• Vatican City, a UN observer state, has a leader elected only by a special class of person that does not necessarily even reside in the nation, the cardinal. All the other priests and other people who live in Vatican City cannot vote in this election.
• Andorra, a UN member state, has two leaders, one elected by the French people—not Andorrans—and the other chosen by the Catholic Church.
• In many jurisdictions of the USA, a UN member state, people convicted of certain crimes cannot vote.

There is one country that has a maximum voting age, namely the aforementioned Vatican City, where the maximum voting age for the enfranchised population is 80.

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Still, it is true that, by and large, most countries do have relatively similar voting criteria. In part, this is because of international law like Article 21 of the Universal Declaration of Human Rights:

The will of the people shall be the basis of the authority of government; this will shall be expressed in periodic and genuine elections which shall be by universal and equal suffrage and shall be held by secret vote or by equivalent free voting procedures.

Overtly violating these rules could potentially lead to UN resolutions, sanctions, and so forth. Countries that that have never followed them, like the aforementioned monarchies, get away with it by tradition, but a country that tried to innovate such a system might face consequences.

In part, it is because of peer pressure and imitating the political systems of countries perceived as more "successful"; it may be particularly relevant here that the USA no longer has de jure poll taxes or literacy tests for voting.

In part, it may be because of domestic appeal. Maintaining the support of the general population is a good way to retain political power, and the general population likes to know that they will have a voice in government. Having fewer voting restrictions is a cheap and easy way to do this.

Less positively, it is because authoritarian governments have largely moved beyond crude disenfranchisement methods in favor of more subtle but equally effective techniques. A literacy test can be foiled by education; a poll tax can be foiled by charitable donation. Simply declaring a certain group should not be allowed to vote will attract international condemnation.

It's much easier, then, to leverage existing, relatively uncontroversial laws to try to disenfranchise people who vote the "wrong" way. For instance, perhaps the people who should not be voting are not really citizens, as with stateless people of Haitian descent in the Dominican Republic. Perhaps the election had voter fraud and was never legitimate to begin with—even better if your political allies are in charge of election authorities and can help prove it. Perhaps the candidate preferred by a group that you want to disenfranchise happens to be disqualified for whatever reason, as in Venezuela.

Answer 2

Some Convergent Evolution, Some Promulgation of Best Practices

Even in nature, structures with little or no common ancestry can develop similar adaptations if they're subjected to similar conditions. Typically (in biology for example) species with convergently evolved traits will inhabit similar biomes/ecosystems, exploit similar niches, and/or be subject to similar selection pressures.

Governmental systems are also subject to selection pressures and insofar as they all govern human beings on Earth, those selection pressures are likely to be virtually identical - especially in the long run. The existence of the internet, UN, and other media through which ideas can job from people to people truly breaks down the idea that these are even separate structures, rather than a single set of best practices being adopted - and proven to a certain extent - to be effective.

Relevant Selection Pressures

Governments that have burdensome requirements on voting essentially have higher transaction costs on relevant voter preference information. They must divert taxes to enforcement/support of those transaction costs and so would be expected to have poorer economic performance ceteris paribus. Therefore simple systems would be preferred unless compelling reasons for specific requirements arise.

Minimum voting age has such a compelling reason. Children aren't in possession of fully developed brains (for that matter, neither are 18 year-olds but they're MUCH closer than even 16 year-olds). There are obvious reasons why they shouldn't be permitted to weigh in on matters they lack the capacity to understand.

Citizenship requirements similarly have a compelling reason. Non-citizens have much less of a stake in the wellbeing of those who live under the regime and furthermore for them to have the power to impose laws on citizens would essentially be a form of oppression. Citizenship requirements ensure that the same People from whom the democratic power is drawn is the People over whom that power is used.

Other systems have been attempted, and generally been the cause of strife and contention. Literacy tests seem to have a compelling interest behind them (only educated people should have sufficient understanding to form meaningfully useful opinions about policy), but a) numerous factors can impact literacy that do not impact fitness to make political choices, b) such systems are trivially easy to corrupt, and c) it is already beneficial to ensure public education exists, which makes moot the primary reason to adopt this.

Property requirements and/or Poll taxes were popular in antiquity and even the founding of the USA, but again - numerous factors can lead to poverty that do not impact the voter's fitness to form meaningful political preferences in an informed manner, and especially if you are operating with an economic system that can produce large disparities of wealth, such systems become extremely oppressive very quickly.

Age-maxima again seem to have a compelling reason... but become very problematic to justify since age also correlates with experience. Any meaningful limit to how old one may be and still vote ends up cutting off quite a body of competent individuals who are otherwise fit to meaningfully contribute. Unlike with children, where brain development is basically guaranteed to be similar, brain deterioration is a decidedly heterogenous process. This makes for a poor filtering criteria due to reliability concerns in the results.

To the extent that these systems largely function well (survive selection pressure) it's not at all surprising that peoples around the world emulate and adopt each other's best practices, that's the natural course of information exchange.

Answer 3

Democratic states all share the same basic presumptions derived from classical Liberal philosophy, central to which is the ideal of broad political equality. You can see that summarized in the U.S. Declaration of Independence:

We hold these truths to be self-evident, that all men are created equal, that they are endowed by their Creator with certain unalienable Rights…

These presumptions were meant to counter the prevailing notion of the then-common aristocratic forms of government, which held that some group of people — the aristocratic class — was more worthy than other groups of people, and thus entitled to greater political power and stronger and more numerous privileges and rights.

Any 'test' for the right to vote is seen as a nod to aristocratic governance, because it privileges one group over others. It doesn't matter what the test is: financial tests (poll taxes), literacy tests, and age tests (maximum age), gender tests (pre-suffrage exclusion of women), a racial tests (exclusion of racially different groups), etc. Any test creates an aristocracy, and thus flies in the face of classical Liberal principles. The only tests that effectively work are age-of-majority tests (a nod to cognitive development issues) and citizenship tests (a nod to nationalism).

Dictatorships that cloak themselves in a democratic facades — of which there are plenty, sad to say — will often subvert this issue by:

1. Restricting legal citizenship to some narrowly defined group, and suppressing all other groups, or…
2. Offering full and equal political participation, but neutering the power of that participation through rigged ballots, intimidation, propaganda, criminalizing dissent, or other techniques.

If one is going to create a Liberal state, one has to invoke Liberal principles (at least for show), and that inevitably leads to some version of flat universal suffrage.

Answer 4

This is like asking why most beer bottles collected after a party contain only an insignificant amount of beer.

Once you have voting system and it is really able to change something, you get represented and not-represented society members in some proportion.

Non-represented members tend to naturally get some extra burden and look for how to deal with it.

The political system has 2 options - either include the non-represented members or deal with them forcefully.

The OP observation is generally the limit where one can safely include almost everyone and still maintain some stability overall.

Who else could be included?

• Non-citizens/non-residents? EU does this to some extent, e.g. in municipal elections. Including them in wider manner could enable a well-known abuse vector: the voting tourism (people voting in a place they don't live and don't get the consequences) .
• Minors? People at age of 18 are minors imho, esp. knowing how much mature I was myself at 18. The age limit varies, but the abuse vector is also well-known: cheap voter manipulation.
• Non-humans? (animals? AI?) - we still don't know.

Answer 5

Your impression "if you're 18-20+ and a citizen, you may come and vote" is incorrect. The majority of the population does not precisely follow this rule, potentially.

1. In UK, you don't have to be an UK citizen to vote. You only have to be a commonwealth citizen and an UK resident. https://commonslibrary.parliament.uk/research-briefings/cbp-8985/

2. In ROC (Taiwan), you cannot vote if you are a ROC citizen. You cannot vote even if you hold a ROC passport. You need to be both a ROC citizen and a formal resident to vote.

3. In PRC, there are two houses: the "lower house" is National People's Congress, and the "upper house" is The National Committee of the Chinese People's Political Consultative Conference. You do need to be a citizen to vote in the lower house, but you don't have to be a citizen to vote in the upper house in the most rigorous legal meanings.

4. In Hongkong, you don't have to be a citizen of any country to vote. All permanent residents can vote.

Those laws and rules potentially affect the voting rights of 1.45 billion people in PRC, ROC, and Hongkong and 2.7 billion commonwealth people, 4.15 billion combined, which is more than half of the global population (8.2 billion).