Andorra is a co-principality; traditionally the princes were the Bishop of Seu-D'Urgell (Spain) and the Compte de Foix (France, whose modern equivalent is the French president). Whilst this still remains the case, the co-princes' power over the Andorran government (constituted in 1993) is now quite limited. Andorra relies on France & Spain for its postal system , and for defence (it has neither of its own). The duty-free limits for travellers leaving Andorra are rigidly enforced, and you can sometimes be stopped by customs officials many kms from the border.