Procedure for Constitutional Amendment

(1) Laws amending the Constitution and other constitutional laws shall be adopted by each Chamber after two successive debates at intervals of no less than three months, and shall be approved by a majority vote of the members of each Chamber in the second voting.

(2) Said laws are submitted to a popular referendum when, within three months of their publication, such request is made by one-fifth of the members of a Chamber or five hundred thousand voters or five Regional Councils. The law submitted to referendum shall not be promulgated unless it be approved by a majority of valid votes.

(3) A referendum shall not be held if the law has been approved in the second voting by each of the Chambers by a majority vote of two-thirds of the members.