The barriers faced by people with disabilities - be they legal or technical - when they want to exercise this right that we nowadays take for granted are still far too high.
National rules in 16 Member States mean that about 800,000 citizens will be deprived of their right to participate in the European Parliament elections as a result of their disability or mental health problems.
Millions of others will have no practical opportunity to vote due to organisational arrangements or technical barriers that do not take into account the needs resulting from their disability.
According to an upcoming report by the EESC - which I produced on the basis of research conducted over two years in 27 Member States - there are some developments that offer hope for the future, but the situation in the EU is still bleak.
Not one single EU country has implemented comprehensive solutions to standardise how all of its polling stations are fitted out and run to ensure that they are user-friendly for all voters.
In fact, in eight Member States, anyone unable to physically get to a polling station will not be able to cast their ballot, since alternative forms of voting - such as postal voting, voting by mobile ballot box or electronic voting - simply do not exist.
In 12 countries, national legislation does not allow the polling station designated on the basis of a person's place of residence to be changed to another that can better accommodate their specific type of disability.
“Not one single EU country has implemented comprehensive solutions to standardise how all of its polling stations are fitted out and run to ensure that they are user-friendly for all voters”
The vast majority of polling stations in the EU are not fully adapted to the needs of persons with different types of disability.
Public authorities often define a polling station as "accessible" if a wheelchair user can enter it, failing to take account of the needs of persons with many other types of disabilities.
This is why in no fewer than 18 Member States blind voters have no way of voting independently; they can only entrust somebody accompanying them to vote on their behalf.
The difficulties most frequently encountered by voters with disabilities include excessively small voting booths that present major difficulties for wheelchair users, and ballot box slots located in such a way that some voters cannot independently insert their ballot paper.
Deprivation of voting rights is particularly worrisome.
Although EU countries have in recent years tended to move away from automatically revoking voting rights for persons with mental health disabilities or problems, nine Member States still do this as soon as someone has their legal capacity removed or has a guardian appointed.
Seven countries limit the rights of these voters on the basis of court decisions taken on a case-by-case basis. In 11 countries an individual can never be deprived of the right to vote.
“Public authorities often define a polling station as ‘accessible’ if a wheelchair user can enter it, failing to take account of the needs of persons with many other types of disabilities”
Only seven EU countries provide special polling stations for voters living in institutions with round-the-clock care or undergoing long-term treatment in hospitals.
In almost one third of EU countries they have no way of voting.
In other countries, while they are theoretically able to vote inside their institution, doing so in practice requires a great deal of support from the voter’s family.
Cumbersome administrative procedures and a lack of relevant electoral information adapted to different types of disability can also act as a deterrent to voting.
Why is that so? The EU Member States are not complying with the rules in force - not only with the United Nations Convention on the Rights of Persons with Disabilities, but also many other international legal and political acts (including the Universal Declaration of Human Rights adopted by the UN General Assembly in 1948, the United Nations International Covenant on Civil and Political Rights and the European Social Charter).
As for the EU Electoral Act, although it did establish many detailed rules for the European Parliament election process, it still failed to safeguard this fundamental right for voters with disabilities.
There are some encouraging examples in the Member States, however.
In eight EU countries, persons with disabilities are allowed to vote by post, and in 12 countries it is possible to vote by ballot box delivered to the voter's current place of residence.
If the best practices from across all countries were implemented, an ideal system would emerge in which every EU citizen with disabilities would not only enjoy full voting rights but would also be able to choose the most convenient way to vote.