It is generally accepted among historians that a fairly extensive set of international legal rules and institutions governed the Greek world. They included customary laws, such as protections for heralds; the rules of treaties, hundreds of which are attested in our surviving sources; and varieties of international arbitration of disputes (Couvenhes; Barta; Giovannini; Low; Bederman; Ager). But we still do not fully understand why Greeks used, complied with, and enforced international law as frequently as they did: practical self-interest? ethics? religious obligation? My twenty-minute paper will argue that, in addition to these factors, the rich array of international networks in the Greek world likely played a role in socializing the decision-makers of many Greek states (polis, koinon, kingdom) so that they were more inclined to use and comply with international legal agreements and rules.
1. Socialization encourages legal compliance. Modern research confirms the well-known phenomenon of socialization: that humans teach each other society’s rules of behavior and also induce each other to internalize and follow those rules. Although much socialization occurs during childhood, at home and school, it is well understood that the process continues throughout life, and that social, professional, and political groups far from the family realm exert what are sometimes decisive socializing pressures. In the contemporary world, international socialization is well documented, by which nations with many connections tend to merge in their legal and other normative behaviors (Goodman and Jinks; Hirsch).
2. International socialization in the Greek world occurred through international networks. Greek historians have recently thrown much light on the rich array of international networks that existed in the ancient Greek world. Elites from multiple Greek poleis encountered and spent time with each other in international contexts such as religious festivals, their associated athletic contests, proxenia networks, international trade, diplomatic meetings, international arbitrations, and via traveling intellectuals such as sophists and poets (Constantakopoulou; Rutherford; Malkin; Ma). Non-elites likely also participated in some of these networks. But although much excellent work has been done in documenting these networks, we are still trying to understand all the effects that they had on Greek life. Isocrates notes in the Panegyricus (4.43) that festivals are an opportunity for people to come together from all over the Greek world, renew old friendships and make new ones, and build up goodwill among Greeks. Social psychologists would call this a process of forming a superordinate group identity, above polis or ethnic identities, and contemporary research indicates that a common result of such superordinate identity formation is a decrease in conflict between the members of the subordinate groups (Hogg 2016).
3. Greek international socialization encouraged international law compliance. The ways that Greeks often talked about international laws suggest that they connected some customary laws—and the obligation to follow them—to their own Greekness. They could be called “the laws of the Greeks” (e.g. by Herodotus, Euripides, Thucydides, Diodorus Siculus), and violations were sometimes seen as “un-Greek.” To the extent that international network interactions helped define and strengthen a “Greek” identity, this evidence suggests that those networks strengthened international law. Thucydides (1.37) has the Corinthians claim that the Corcyreans, at the edge of the Greek world, had less contact with other Greeks and therefore were less prone to use Greek international legal institutions such as arbitration. Although arguably incorrect in the case of Corcyra, the argument reveals that some Greeks connected international law compliance with close connections to the rest of the Greek world.
Adriaan Lanni has recently taken what can be described as a generally sociological approach to explaining why Athenians were largely law abiding in the context of domestic law. In this paper I will try to explain a similar phenomenon, but in the larger realm of Greek international law.