Q.EU tried and failed to create a European constitution. Does this always happen in constitution-making?

How a constitution comes into being — who actually crafted it and how much genuine authority those framers possessed — is one of the most important factors in whether that constitution goes on to be effective or remains a dead letter. Constitutions crafted by unpopular military rulers, or by leaders without real public support, very often remain defunct even after they are formally adopted, precisely because they never had genuine legitimacy to start with. By contrast, some of the most successful and durable constitutions in the world — India's, South Africa's, and the United States' — were all created in the aftermath of popular national movements that had already earned wide public trust well before the constitution itself was drafted. India's own Constituent Assembly sat formally between December 1946 and November 1949, but its deeper authority rested on decades of the nationalist movement's own history of bringing diverse sections of Indian society together. Because the Constitution was framed by leaders who already had enormous public credibility and were trusted not to be using the process for their own personal power, the final document commanded broad national consensus even though it was never actually put to a public referendum, unlike in some other countries. Nepal's own repeated failure to produce a lasting constitution — five different constitutions between 1948 and 1990, each simply granted by the reigning monarch rather than made through any genuinely popular process — versus its eventual success only after the monarchy's abolition and a real constituent-assembly process culminating in the 2015 constitution, is a vivid real-world illustration of just how much mode of promulgation matters.