Portugal - 1997 Constitution

Part III - Organization of Political Power - III - Assembly of the Republic
Title Article 160
Chapter I - Statute and Election
Article

160

(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 163 (1976)
Categories - Electoral party (Fielding candidates)
- Parliamentary party (Relationship MPs with EPO)
Source Portuguese Electoral Commission (http://www.cne.pt)