Andorra is a parliamentary democracy, so the monarchs' power are very limited. Neither of the Co-Princeps have the power to determine the foreign relations of Andorra, or to determine trade or treaty obligations. With respect to international relations, Article 44 of the constitution states that:
- The Coprínceps are the symbol and guarantee of the permanence and continuity of Andorra as well as of its independence and the maintenance of the spirit of parity in the traditional balanced relation with the neighbouring States. They proclaim the consent of the Andorran State to honour its international obligations in accordance with the Constitution.
(Their power is limited to proclaiming that Andorra will not be a scrub).
The constitution of Andorra grants the coprinceps the powers to:
- The Coprínceps may perform the following acts of their free will:
a) The combined exercise of the prerogative of grace.
b) The creation and structuring of the services considered to be necessary for the performing of their institutional functions, the appointment of the holders of these services and their accreditation to all effects.
c) The appointment of the members of the Consell Superior de la Justícia, in accordance with article 89.2 of the Constitution.
d) The appointment of the members of the Tribunal Constitucional, in accordance with article 96.1 of the Constitution.
e) The requirement of a preliminary judgment of unconstitutionality of the laws.
f) The requirement of a judgment about the unconstitutionality of international treaties, prior to their ratification.
g) The lodging of conflict before the Tribunal Constitucional in relation to their constitutional functions, under the provisions of articles 98 and 103 of the Constitution.
h) The granting of the agreement for the adoption of the text of an international treaty, in accordance with the provisions of article 66, before its parliamentary approval.
- The acts derived from articles 45 and 46 are exercised by the Coprínceps personally, except for the faculties provided for in letters e), f), g), and h) of this article, which may be performed by delegation.
I haven't found any evidence that either of the princes has exercised the powers granted under the constitution, however there was one action in 1993
In 2009, French president Nicolas Sarkozy threatened to abdicate as Andorran Co-prince if the principality did not change its banking laws to eliminate its longstanding status as a tax haven.