The Need to Conceptualize Reciprocity in International Relations

Despite the incorporation of definition and association in the field of international relations, there is a need to contextualize these concepts and transform them into a pragmatic reality. This pragmatic reality must be made accessible to states and practitioners, and its concepts must be comprehensible to students. The concept of reciprocity is of paramount importance, and its significance will be explored here within the context of international relations and diplomacy.

What is the principle of reciprocity?

In a system of sovereign equals where no global government exists, reciprocity serves as a “meta-rule” or mechanism to maintain balance (Whelan, 2023).

It is imperative to acknowledge the existence of three distinct forms of reciprocity: legislative, diplomatic, and de facto.

Legislative reciprocity

In the context of property law or inheritance law, a state’s legal framework may explicitly grant rights to foreign nationals, but only under the condition that the foreign national’s home country also grants those same rights to its own citizens.

Diplomacy reciprocity

Practical mutual treatment among diplomats and embassies is demonstrated by the reciprocal granting of tax exemptions or immunities.

De facto reciprocity

A dynamic that emerges when states accord each other equitable treatment in practice, even in the absence of a formal written treaty or legal instrument.

This occurrence is indicative of a fundamental structural reality: namely, that all states are considered equal in formal standing. Consequently, the assertion of a right by one state must be accompanied by an acknowledgement of the corresponding entitlement of other states. The concepts of rights and obligations are frequently intertwined, with the performance of one party often contingent on the performance of the other.

The principle of reciprocity is a frequent reliance point for the International Court of Justice (ICJ) in matters pertaining to treaty law and dispute settlement. Similarly, in the context of extradition and enforcement, the ICJ frequently employs a reciprocal approach to jurisdiction.

Given these definitions, it becomes evident that the principle is founded on the tenet of equality. Nevertheless, the term “equality” should be employed exclusively in instances where the two entities in question are demonstrably equivalent in terms of magnitude, capacity, or other pertinent metrics. For instance, the United States, France, and the United Kingdom are nations that are not analogous to Somalia, Ecuador, or Laos.  In the event of a disparity in the characteristics that serve as the basis for the comparison of states, the principle of reciprocity undergoes a transition from equality, and subsequently to parity.

Why parity?

To understand the concept of parity, it is imperative to clarify the principle of retorsion.

The principle of retorsion is defined as the lawful “tit-for-tat” retaliation by one state against another’s unfriendly, discourteous, or harmful acts. Retorsion is defined as a set of actions that are deemed lawful under the precepts of international law. Such actions may include the expulsion of diplomatic representatives, the imposition of travel restrictions, or the enactment of economic sanctions. These measures are employed as a means of expressing discontent without the violation of existing treaties (Oxford Public International Law).

It has been observed that nations of considerable power have frequently implemented travel restrictions against citizens of less powerful nations. In response, the latter nations have often adopted similar restrictions, thereby engaging in a reciprocal pattern of retaliation. Nevertheless, the potential impact on a major global power must be assessed to ensure the validity of the proposed course of action.

Case study: Nigeria and the US

According to recent estimates, the number of Americans who visit Nigeria annually ranges from 80,000 to 120,000. The United States is a leading source of international travelers to Nigeria, often accounting for 3% to 5% of the total annual inbound arrivals (Statista, 2022).

Despite the absence of comprehensive, current data regarding American students enrolled in Nigerian educational institutions, available data suggests that the number is relatively small. The American International School of Lagos (AISL) reported approximately 103 US citizens among its 470+ students in the 2023–2024 academic year, making it one of the most prominent expatriate educational institutions in the country (US Department of State).

In 2024, approximately 116,969 Nigerian citizens traveled to the United States. This figure signifies a modest rise from the 114,263 visitors documented in 2023. Despite the high level of interest in travel, Nigerian applicants encounter substantial obstacles, including a high rate of visa denials and recent policy changes that have become more stringent (Statista, 2025). For the 2023–2024 academic year, the number of Nigerian students enrolled in US institutions increased by 13.5% compared to the previous year, reaching over 20,000.

A comparison of the rates at which Americans and Nigerians visit each other’s countries indicate similar levels of international mobility. It would be imprudent for Nigeria to respond to the increasing difficulty in traveling due to recent policy changes through reciprocation and imposing a visa ban on Americans, as the repercussions would be negligible, particularly among the student population.  In addition, the United States is a major foreign investor in Nigeria. In 2024, US Foreign Direct Investment (FDI) reached $7.9 billion, representing a 25.2% increase from the previous year (Energy News Network). Therefore, it can be posited that, in the hypothetical scenario in which the United States were to impose a travel ban on Nigeria, it would be imprudent for Nigeria to invoke the principle of reciprocity as it is currently conceptualized, which is predicated on the tenets of equality.

The concept of retorsion, defined as the implementation of economic sanctions as a form of retaliation against a travel band, should be founded on the principle of parity. In this context, Nigeria should prioritize the interests of other competitive investors over those of the United States. This strategic approach, encompassing sectors such as mining, oil, and other strategic resources, could be employed to harm the interests of the United States and other major powers.

Bibliography

Whelan A. “What Is Reciprocity?”, Reciprocity in Public International Law. Cambridge Studies in International and Comparative Law. Cambridge University Press; 2023:43-68.

Oxford Public International Law, published under the auspices of the Max Planck Institute for Comparative Public Law and International Law under the direction of Professor Anne Peters (2021–) and Professor Rüdiger Wolfrum (2004–2020).

Statista, “Most common countries of origin of tourists arriving in Nigeria in 2022”.

US Department of State, “Lagos, Nigeria: American International School of Lagos: 2023-2024 Fact Sheet”.

Statista, “Number of visitors to the US from Nigeria 2011-2024”, published 28 November 2025.

Energy News Network, “How US-Chinese investment models are reshaping Nigeria’s trade energy sector”.