The Security Studies Seminar is a monthly seminar series that aims to comprehensively discuss a new piece of academic research on matters pertaining to Indian and international security, with the author.

There have been only two instances of direct armed conflict with non-trivial fatalities between nuclear powers so far: the 1969 Sino-Soviet border conflict that started on the Zhenbao Island on the Ussuri River, and the 1999 Kargil conflict between India and Pakistan. In his new paper, Abhijnan Rej develops a new offense-defense balance (ODB) theory for limited wars under the nuclear overhang and tests its validity against these two cases. 

Carnegie India hosted Abhijnan Rej, an independent researcher, for a discussion on the ODB under the nuclear overhang during the 1969 Ussuri border clashes and the 1999 Kargil conflict. The discussion was moderated by Srinath Raghavan, senior fellow at Carnegie India. 


  • War Initiation: Examining why war breaks out between states, participants reasoned that a state will attack an adversary if it perceives certain military advantages in doing so. On the contrary, if a state perceives defending potential attacks to be more advantageous, it will not initiate war. Thereby, this balance of offense and defense between adversarial states determines whether they will initiate war. Furthermore, participants probed why states assess variables like military capabilities, geographical advantages and vulnerabilities, and diplomatic relations while calculating the ODB.
  • Limited Wars: Participants explained that, in contrast to total wars that aim to incapacitate and destroy the enemy, belligerents aim to seize and hold a fraction of the enemy’s territory during limited wars. Participants proposed a new version of the ODB theory to explain why states initiate limited wars under the nuclear overhang. They postulated that, under these circumstances, belligerents account for military inventories, the geographical features of the theater of war, and the prevailing attitude of the military toward domestic institutions to calculate the ODB. More importantly, they hypothesized that since the attacker aims to limit the possibility of war, it will discount its own and the adversary’s nuclear capabilities. To test this theory, they considered two case studies: the 1969 Ussuri border clashes between the Soviet Union and China, and the 1999 Kargil conflict between India and Pakistan. They pointed out that in addition to being limited wars fought under the nuclear overhang, these two cases studies also help illuminate a weaker power’s (China in the Ussuri conflict and Pakistan in the Kargil conflict) calculus in initiating the conflict.  
  • Analyzing the ODB Theory: Participants emphasized that during the Ussuri clashes, the Chinese side enjoyed an advantageous local military balance and a favorable terrain that assured short supply lines. They also discussed how, as hypothesized, Mao discounted Chinese nuclear capabilities due to insufficient delivery material. He had also discounted Soviet nuclear capabilities since he believed that there were no concentrated Chinese targets to hit, by which the Soviet forces could gain advantage, they added. Participants highlighted that based on these considerations, despite being the weaker side, the Chinese chose to attack Russian troops. Likewise, while analyzing the Kargil conflict, participants highlighted that, despite India’s overall conventional superiority, the local military balance was in in Pakistan’s favor after they gained control of two strategically crucial points early on during the conflict. While participants highlighted that Pakistan discounted its own nuclear capability due to limited operability, they questioned whether it discounted Indian nuclear capabilities from the very beginning of the conflict. Hence, some participants contested the theory’s explanatory power and argued that overlaps between the two case studies may be coincidental. They suggested including several other case studies to test the theory’s validity and identify which variables affect the ODB. 

The summary was prepared by Raghuveer Nidumolu, Knowledge Transfer program coordinator, with inputs form Megha Gupta, a research intern at Carnegie India.