The theory of international trade is dominated by a model presupposing a legal order that is perfect in its specifications and controllability, binding for all economic agents, no matter their nationality. World order appears to be cosmopolitan, as defined by Kant [20]. An international private law community such as this, however, does not exist. In fact, there is a territoriality of law, leading to problems largely neglected in the traditional theory of international trade. They are at the heart of what we would like to call the New Institutional Economics of International Transactions (NIEIT) [29; 30; 31; 32; 33]. These problems can best be described in the terminology of property-rights analysis. Economic transactions consist of an exchange of property rights, that is, of sanctioned behavioural relations [13, 1139]. While for domestic trade the legal foundation and its enforcement through the protective [7, 68, 85] are unequivocal, international transactions touch a multitude of legal systems and the monopoly of power claimed by each state within its boundaries. Collisions of norms and gaps between different norm systems then appear. An accord in judicial decisions is often coincidental, and the assistance of the judicial and penal institutions in foreign countries is not at all a matter of course. Thus, because of the absence of a world state, the property rights of economic agents involved in private international trade are often incompatibly defined and insufficiently protected. Consequently, the territoriality of law results in a specifically high amount of uncertainty that we call the constitutional uncertainty in international trade. For agents involved in foreign trade this kind of uncertainty poses coordination problems of a special type. They are reflected in transaction costs, i.e., the costs of coordinating the economic activities among individuals. Consider the following examples [33, 27; 30, 50]: In the year 360 B.C.-as is reported by the Greek author Demosthenes-Zenothemis and the shipowner Hegestratos convinced traders of Syracuse to advance money to them upon declaring untruthfully that their vessel was fully laden with corn belonging to them. The two swindlers sent the money to Massalia, and three days after sailing, Hegestratos tried to scuttle the vessel in order to circumvent the repayment of the credit. But the passengers were alert, and the scuttling attempt failed. Nevertheless, we have reason to believe that the Syracusian traders never saw their money again [19, 4].