Who can initiate an optional referendum at the national level?

Constitutionof the Principality of Andorra

Article45

TheCoprinces, with the countersignature of the Head of Government, or whenappropriate, of the Syndic General, have the political responsibility for:

b)Calling a referendum in accordance with articles 76 and 106 of theConstitution.

Article76

TheHead of Government, with the approval of the majority of the General Council,may request the Coprinces to call a referendum on political matters.

Article 43

1.In accordance with the institutional tradition of Andorra, the Coprinces are, jointly and indivisibly, the Head of State, and they assume its highest representation.

2.The Coprinces, an institution which dates from the Pareatges and their historical evolution, are in their personal and exclusive right, the Bishop of Urgell and the President of the French Republic. Their powers are equal and derive from the present Constitution. Each of them swears or affirms to exercise their functions in accordance with the present Constitution. 

Qualified Law 28/2007, of November 22, amendingQualified Law on the Electoral System and Referendum

ChapterTwo. The advisory referendum

Article72. Call for advisory referendum

Thehead of the Government shall request the co-princes to call a referendum onpolitical matters, when its holding is approved in accordance with theprovisions of the Constitution.