Portugal - 1976 Constitution

Part III - Organization of Political Power - IV - The Assembly of the Republic
Title Article 163
Chapter I - Statute and Election
Article

163

(1) Deputies shall cease to hold office if they:
c) join a different party from the one that nominate them for election;

Amendment Constitution: Article 160 (1997)
Categories - Electoral party (Fielding candidates)
- Parliamentary party (Relationship MPs with EPO)
Source Portuguese Electoral Commission (http://www.cne.pt)