Given in Rome on this 27th Day of December 1947 ENRICO DE NICOLA Countersigned The President of the Constituent Assembly : UMBERTO TERRACINI The President of the Council of Ministers : ALCIDE DE GASPERI The Keeper of the Seal : GIUSEPPE GRASSI In order to make it virtually impossible to replace with a dictatorial regime it is difficult to modify the Constitution ; to do so ( under Article 138 ) requires two readings in each House of Parliament and if the second of these are carried with a simple majority ( i.e. 50 % +1 ) rather than two-thirds a referendum .