Private International Law: Between Necessity and Opportunity

There is no better place for reflection on law, and more specifically on one of its branches, than a forum of lawyers. If we start from the premise that law arises to regulate the various aspects of reality, practice must provide the foundation for any construction of legal theory on which to base any discipline. It is in this context that I venture to offer these brief reflections on the relevance and nature of private international law (PIL) in today’s globalized world.

From a purely practical perspective, lawyers consider PIL to have become one of the most significant disciplines in recent years. Such a statement is not entirely without justification. However, it is worth looking back if we wish to understand the present and analyze its significance.

In this sense, it does not seem audacious to trace the origin of the first regulations of international private situations (or legal relations with a foreign element) to commercial relations. Perhaps stemming from medieval commercial law developed by the merchants themselves, which reinforced the break with the feudal system and transformed not only the economic model but also social and cultural spheres. As A. Roncero Sánchez notes, trade involves exchange, relationships between parties from different places, and consequently the transfer of ideas, fashions, customs, and, of course, personal relationships. Indeed, beyond the distant precedents rooted in the legal systems of Ancient Greece or the Roman Empire, the rule Statutum non ligat nisi subditos, devised by the Bolognese jurist Francesco di Accursio (1182–1263), seems to mark the birth of PIL. Crossing a border should not entail a change in the applicable law in order to enable an international market. This is the meaning of the maxim, which relied on applying the law of the individual’s country of origin and today could be interpreted as the need to ensure continuity in legal relations across borders.

The international trade dilemma, brilliantly described by F. Garcimartín Alférez, helps us understand the role of PIL in international commerce, which is to say, extrapolating some concepts, in all private relations with a foreign element. According to the trade dilemma—which is a variant of the prisoner’s dilemma in game theory—two isolated parties in a hypothetical stateless world, even if they improve their living conditions (in the Pareto sense) through specialization and the exchange of goods and services, would tend to avoid cooperation. In reality, all human exchange relationships presuppose a difference in the value the parties assign to the objects being exchanged and entail a gain for all participants. If A values a painting at €900, and B values the same painting at €1,100, a sale agreed at €1,000 represents a gain for both. However, from a game theory perspective, the option to breach the contract is Pareto-superior. For the seller, failing to deliver the goods might result in either a 100% gain of the price if the buyer pays, or no gain/loss if the buyer defaults. Delivering the goods exposes the seller to a 100% loss if the buyer refuses to pay, or to a profit margin (in our example, €100). The buyer faces a similar analysis.

It is the state, through law and the judiciary, that provides the necessary legal security to contracting parties, ensuring that in the event of breach, the compliant party’s rights are safeguarded, thus counterbalancing the higher efficiency of the breaching option.

In international trade, the situation is even more complex due to the diversity of national legislations and judicial systems worldwide. Overcoming the international trade dilemma therefore requires the application of PIL rules. International civil procedural law and applicable law provisions provide the necessary legal certainty in international commerce. Rules on international jurisdiction clarify which courts parties can approach, while conflict-of-law rules determine which substantive law applies. These are complemented by recognition and enforcement rules, which prevent unenforceable decisions across different states.

In family law, interests differ significantly from those in property relations. Efficiency and the trade dilemma do not serve as a theoretical framework. Yet both types of relations—property and family—share a common need: ensuring the continuity of legal relations across borders. In both cases, we are dealing with international private situations or private legal relations with a foreign element, which constitute the subject of the discipline. However, in property relations, PIL also plays a preventive and promotional role, which does not occur in family relations, which are not subject to this purpose by their nature.

Returning to practical considerations, both the need to overcome the international trade dilemma and to ensure continuity in legal relations derive from the existence of multiple legal systems. This is one of the assumptions of the discipline, which focuses attention on the debate about unifying law. This is not the space to expand on the unification of substantive law, widely discussed in legal doctrine. It suffices to note that today’s context of globalization—or post-globalization, if we consider recent thought currents like Andrej Statskij’s Future of Globalization (2002)—points to the existence of common or “transnational” rules, irrespective of their state or private origin. Perhaps we could speak of a global law regulating legal relations with and without a foreign element, in which the main actors are the operators themselves, and where party autonomy plays a leading role.

In this sense, the influence of party autonomy in regulating international trade is evident and constitutes a key factor in defining contract law regimes. Party autonomy is in fact an essential component of a private law system. In international commerce, the parties’ will is a primary criterion for international jurisdiction (express or tacit submission) and the first conflict-of-law rule of European private international law (Art. 3 of Regulation 593/2008 of June 17, 2008—Rome I). Therefore, party autonomy codified in PIL rules is the most appropriate solution to overcome the international trade dilemma. However, it is necessary to distinguish between two types of autonomy: conflictual, which allows choosing an applicable national law for the contract, and material, which permits incorporating substantive rules governing different aspects of the contractual process. The Legal Guide on Uniform Instruments in the Field of International Commercial Contracts, with Emphasis on Sales, published in 2020 by UNCITRAL, the Hague Conference, and UNIDROIT, emphasizes the relationship between these two aspects of party autonomy and the critical importance of determining the law applicable to contracts. Incorporating clauses and agreements (material autonomy) ultimately depends on the law applicable to the contract (conflictual autonomy).

In family law, the long-standing tension between party autonomy and public order is much more evident than in property law. Nevertheless, in recent years, spurred by international human rights treaties, party autonomy has been gradually gaining ground, as evidenced by European PIL regulations governing family relations (Art. 5 of Regulation 1259/2010 on the law applicable to divorce and judicial separation, and Art. 22 of Regulations 2016/1103 and 2016/1104 on matrimonial property regimes and registered partnership effects), international codification (Arts. 7 and 8 of the Hague Protocol on the Law Applicable to Maintenance Obligations, 2007), and autonomous private international law in certain states. As Cristina González Beilfuss notes, party autonomy in family law remains an emerging trend rather than a widely recognized right, and has yet to attain the status of a general principle.