Plato, through the character of Socrates, advances a now classic argument against democracy. When it comes to a matter that requires knowledge and skill, such as a medical issue, it would be foolish to decide by having the ignorant vote on the matter. Those who have good sense turn to those who have the knowledge and skill needed to make a good decision.
Political matters, such as deciding what policies to adopt regarding immigration, require knowledge and skill. As such, it would be foolish to make decisions by having the ignorant and unskilled vote on such matters. Picking a competent leader also requires knowledge and skill and thus it would be foolish to leave it to those lacking these attributes.
In the abstract, this argument is compelling: as with all tasks that require competence, it would be best to have the competent make the decisions and the incompetent should remain on the sidelines. There are, however, various counters to this argument.
One appealing argument assumes people have a moral right to a role in decisions that impact them, even if they are not likely to make the best (or even good) choices. Consider, for example, something as simple as choosing a meal. Most people will not select the most nutritious or even most delicious option, thus making a bad choice. However, compelling people against their will to eat a meal, even if it is the best for them, seems to be morally problematic. At least when it comes to adults. Naturally, an argument can be made that people who routinely make poor health choices would be better off being compelled to eat healthy foods—which is the heart of this dispute between democracy and being ruled by those with the knowledge and skills to make better decisions.
Another approach is to use the context of the state of nature. This is a philosophical device developed by thinkers like Locke, Hobbes and Rousseau in which one is asked to imagine a world without a political system in place, a world in which everyone is equal in social status. In this world, there are no kings, presidents, lawyers, police or other such socially constructed positions of hierarchy. It is also assumed there is nothing supernatural conferring a right to rule (such as the make-believe divine right of kings). In such a context, the obvious question is that of what would give a person the right to rule over others.
As a practical matter, the strongest might coerce others into submission, but the question is one of the right to rule and not a question of what people could do. Given these assumptions, it would seem that no one has the right to be the boss over anyone else—since everyone is equal in status. What would be required, and what has often been argued for, is that the consent of the governed would be needed to provide the ruler with the right to rule. This is, of course, the assumed justification for political legitimacy in the United States and other democratic countries.
If it is accepted that political legitimacy is based on the consent of the governed, then the usual method of determining this consent is by voting. For a country to continue as one country it must also be accepted that the numerical minority will go along with the vote of the numerical majority—otherwise, as Locke noted, the country would be torn asunder. This is, as has been shown in the United States, consistent with having certain things (such as rights) that are protected from the possible tyranny of the majority.
If voting is accepted in this role, then maintaining political legitimacy would seem to require two things. The first is that there must be reliable means of assuring that fraud does not occur in elections. The United States has done an excellent job at this. While there are some issues with the accuracy of voter lists (people who move or die often remain on lists for years), voter fraud is almost non-existent, despite unsupported assertions to the contrary.
The second is that every citizen who wishes to vote must have equal and easy access to the voting process. To the degree that citizens are denied this equal and easy access, political legitimacy is decreased. This is because those who are deterred or prevented from voting are denied the opportunity to provide their consent. This excludes them from falling under the legitimate authority of the government. It also impacts the legitimacy of the government in general. Since accepting a democratic system means accepting majority rule, excluding voters impacts this. After all, one does not know how the excluded voters would have voted, thus calling into question whether the majority is ruling or not.
Because of this, the usual attempts to deter voter participation are a direct attack on political legitimacy in the United States. These include such things as voter ID laws, restrictions on early voting, unreasonable limits on polling hours, cutting back on polling places and so on.
In contrast, efforts to make voting easier and more accessible (consistent with maintaining the integrity of the vote) increase political legitimacy. These include such things as early voting, expanded voting hours, providing free transportation to polling stations, mail in voting, online voter registration and so on. One particularly interesting idea is automatic voter registration.
It could be argued that citizens have an obligation to overcome inconveniences and even obstacles to vote; otherwise they are lazy and unworthy. While it is reasonable to expect citizens to put in a degree of effort, the burden of access rests on the government. While it is the duty of a citizen to vote, it is the duty of the government to allow citizens to exercise this fundamental political right without undue effort. That is, the government needs to make it as easy and convenient as possible. This can be seen as somewhat analogous to the burden of proof: the citizen is not obligated to prove their innocence; the state must prove their guilt.
It could be objected that I only favor easy and equal access to the voting process because I am registered as a Democrat and Democrats are more likely to win when voter turnout is higher. If the opposite were true, then I would surely change my view. The easy and obvious reply to this objection is that it is irrelevant to the merit of the arguments advanced above. Another reply is that I actually do accept majority rule and even if Democrats were less likely to win with greater voter turnout, I would still support easy and equal access. And would do so for the reasons given above.