In reply to this question, the author gives a negative answer. In Latin American constitutions, the citizen’s (person’s) duties are, at the same time, too ample and too narrow. On one hand, the constitutional obligations imposed on individuals — owing to their scope — exceed the possibilities of their fulfillment. For instance, it is hard to imagine a realization by a single person of the obligation of “the conservation of cultural and natural heritage as well as the care for the public goods”. On the other hand, there are duties that strike us with their exaggerated minuteness, incoherent with the nature of a fundamental national charter. One should mention here the Honduran citizens’ obligation to obtain their identity card or the duty of Mexicans to participate “in days and hours determined by the municipal authorities of place of residence in civic and military training”. Furthermore, the constitutional duties are not accompanied by any sanctions or tools forcing their implementation. The mandatory voting — when violated — remains unpunished. Usually, the amnesty (abolition) acts are proclaimed after the elections. They exempt the citizens defaulting their duty to vote from, for example, fines, if any. Even if such statute is not adopted, the punishability of abstaining from going to the polling station is relative in nature. In Peru, the only consequence of such behavior is an impossibility to use of a non-validated electoral identity card as a substitute of ID before public organs. Finally, it is unacceptable to make the equation, in the constitutions, between duties and rights. It is very difficult to have simultaneously a right and an obligation of its possession and/or assertion. The duty is always the limitation of a free choice of behavior. Its standard understanding means an ordered or prohibited conduct of the norm’s addressee, according to its content. Even the tautological definition of a constitutional duty — a state of affairs which should be assured by a party obliged — does not leave room for recognition, liberty or entitlement. The Latin American constitutional documents contain too many duties (obligations). In some countries their number amounts to about twenty (Ecuador, Bolivia, Mexico). If we adhere to the opinion that every right is, at the same time, an obligation, they will be countless. For that reason, I believe — after D. Diderot — that there is one sole obligation, that is to be happy. It is the only source of every genuine duty, and the exclusive basis for good law-making.