Graduate students and faculty from the Graduate School of Arts and Science at New York University conducted a replication study of the Thucydides Trap Project developed by the Belfer Center at Harvard University in 2015. The Thucydides Trap case file was the foundation for Graham Allison's hypothesis in his book "Destined for War: Can America and China Escape Thucydides's Trap?" and in his essay "The Thucydides Trap: Are the U.S. and China Headed for War," published in the Atlantic on September 24, 2015. In his analysis, Allison concluded that, given that 12 out of 16 cases between rising and ruling power ended in war, the likelihood of a similar fate for the United States and China was high. 

Research Significance

The Thucydides Trap Project has gained significant attention, particularly amid the ongoing tensions in U.S.-China relations. Consequently, research from the Harvard Belfer Center and Graham Allison's hypothesis, which utilizes the Center's case studies, is attracting increased interest from political scientists, academics, and policymakers.

We believe that our replication research will be a significant contribution to political science. As Harvard University professor Gary King explains in his article "Replication, Replication," published in the journal PS: Political Science and Politics in 1995, "The most common and scientifically productive method of building on existing research is to replicate an existing finding - to follow the precise path taken by a previous researcher, and then improve on the data or methodology in one way or another...Unfortunately, a recent study indicates that the modal number of citations to articles in political science is zero: 90.1% of our articles are never cited." 1 

Research Objective

The project aims to identify instances since 1500 when a rising power threatened to displace a ruling power, resulting in war or no war. To achieve this objective, the Center used primary, secondary, and tertiary documents.

Research Question

While the original project sets forth its objectives, it does not clearly define a specific research question. Based on the variables presented, we formulated the main research question: Is war inevitable when a rising power threatens to displace a ruling power?

Hypothesis

When a rising power threatens to displace a ruling power, the likelihood of war increases.

Variables and Operationalization

The Center suggests that the independent variable is a rapid shift in the balance of power (correlation of forces) between a significant ruling power and a rising rival that could displace it. Their dependent variable is war (a military conflict causing a minimum of a thousand fatalities per year). Moderating variable(s) could be economic interdependence, nuclear deterrence, and international organizations.

The Center defines its dependent variable as war, following the standard criteria established by the Correlates of War Project. However, we believe that choosing war as the dependent variable is problematic. War is often the culmination of tensions before the onset of war, such as diplomatic tensions or economic competition. To accurately capture the complexity of interstate relations, the dependent variable should instead be the quality of bilateral relations between the states involved.

The Center does not formally operationalize the terms "ruling power" and "rising power," but they indicate that these concepts are based on the history books they used. "Rising power" refers to a state rapidly gaining influence through economic and military expansion, while "ruling power" denotes the dominant entity.

Temporal Coverage

 1500-2000s (500 Years) 

Research Type

The research is boldly explanatory, aiming to identify causal factors and outcomes of the phenomenon. However, the main research question leans more towards a descriptive approach. "Explanatory research seeks explanations of observed phenomena, problems, or behaviors. While descriptive research examines the what, where, and when of a phenomenon, explanatory research seeks answers to why and how types of questions." 2 

Research Design

The Belfer Center utilizes a comparative case study to analyze 16 cases with well-defined temporal coverage.

Research Method and Methodology

The project primarily employs a qualitative method with quantitative elements and follows a deductive reasoning approach. It begins with a theoretical proposition and then introduces historical case studies. Additionally, the Center utilizes secondary document analysis, drawing on books and scholarly articles; however, the research mainly relies on one key source - "The New Cambridge Modern History” – “Where there were significant differences in interpretation, we have relied on The New Cambridge Modern History as referee.”3 

Theoretical Framework

The Belfer Center does not explicitly state which theoretical approach they employ in this project, but their analytical framework predominantly aligns with classical realism. It emphasizes concepts related to the balance of power, power transition, and the security dilemma. While some of these specific terms are not directly referenced, the underlying logic of their analysis embodies these ideas. Furthermore, the notion of the Thucydides Trap is grounded in the Peloponnesian War between Sparta and Athens, which illustrates the dynamics of power transition. As such, the Peloponnesian War is a foundational case study in classical realism within international relations theory.

Endnotes

1. Gary King, “Replication, Replication,” PS: Political Science and Politics 28, no.3 (1995): 445.

2. Anol Bhattacherjee, Social Science Research: Principles, Methods, and Practices (Tampa, FL: University of South Florida, 2012), 6.

3. Belfer Center for Science and International Affairs. “Resources and Methodology.” Thucydides’s Trap. Harvard Kennedy School. Accessed April 10, 2025. https://www.belfercenter.org/programs/thucydidess-trap/thucydidess-trap-resources-and-methodology