Harvard v. NYU

Before proceeding with a comparison of the final results of the NYU GSAS Replication Study to the original research conducted by the Harvard Belfer Center, it is essential to exclude cases primarily driven by religious, monarchical, or dynastic rivalries. While such conflicts between rising and ruling powers may qualify as classic examples of the Thucydides Trap scenario, they do not apply to the contemporary U.S.-China relations.

In the replication study, we excluded cases II (The Habsburgs vs. France), III (England vs. The Habsburgs & France), and VI (Great Britain vs. France) from the probability calculation of war occurrence, as these cases clearly illustrate instances of imperial succession and religious conflict. Out of the 21 cases of the replication study, we retained 18. Among these, 12 resulted in war while six ended peacefully, leading to a war probability of approximately 66.7% (or two-thirds). However, it is essential to note that this figure is not the final determination for assessing the likelihood of war or peace.

In Harvard's original project, after excluding dynastic and religious rivalries  - specifically, Cases II (France vs. the Habsburgs) and VI (France vs. the United Kingdom)  - 14 cases remain. Out of these, 10 resulted in war, while four concluded peacefully. This results in a war probability of 71.4%, which is higher than that found by NYU.

The percentages cited are not yet conclusive. In the replication study, 5 cases are from the pre-Westphalian period, 14 cases are from the Westphalian period, and only two are from the post-Westphalian period or rules-based order (the most relevant to US-China relations). Harvard has two cases from the post-Westphalian period as well. Notably, both the replication study and the original project indicate that none of the power struggles between rising and ruling powers have escalated into direct military conflict during the post-Westphalian period. The rules-based international order, characterized by new elements such as nuclear deterrence, economic statecraft (more economic tools), high economic interdependence, improved information exchange, and cyber capabilities, significantly transforms the landscape of interactions between states.