US Entry into the Korean War: Origins, Impact, and Lessons
Nuclear Weapon Use Risk Reduction

US Entry into the Korean War: Origins, Impact, and Lessons

This special report by James I. Matray looks back on the historical events that led to the US entry into the Korean War in 1950 and draws lessons about the use of nuclear weapons in future conflict on the Korean peninsula.

Matray argues that the Soviet Union’s possession of atomic bombs in June 1950 played no role in the start of the Korean War and therefore the DPRK’s attack on the ROK provides no analogs for how nuclear weapons might motivate a nation, currently, to initiate a conflict. However, because neither Pyongyang nor Beijing had nuclear weapons during the Korean War, the US could consider using atomic bombs at a few key moments as the war unfolded. Lessons from the Korean War suggest that a nation acting alone in a future war would be more likely to use nuclear weapons than one wanting to maintain the support of allies.

Contemplating the likelihood of the use of nuclear weapons on the Peninsula, Matray concludes that a new Korean War is improbable for the following reasons:

  1. US Commitment to Protect the ROK: US military forces remain deployed in the ROK, and they would sustain casualties in the event of a DPRK attack, guaranteeing massive American military retaliation. The US also has a legal obligation to defend the ROK if the DPRK attacks under the 1954 US-ROK Mutual Security Treaty.

  1. DPRK no longer contemplates an attack on the ROK: Pyongyang has not developed nuclear weapons capabilities as part of plans to resume hostilities, but, instead, to deter a US-ROK attempt to destroy the DPRK that almost succeeded in the fall of 1950. Pyongyang understands that a nuclear attack on the ROK would ignite a blistering counterattack resulting in its annihilation.

  1. Lack of Support for the DPRK: There is no longer a Soviet Union to provide the DPRK with the weapons and supplies it would need for a serious offensive. Moreover, China would not support a military assault and probably would withhold the oil that the DPRK would need to sustain an invasion.

  1. DPRK’s Weak Conventional Military Capabilities: DPRK’s conventional military capabilities are not sufficient to overwhelm the ROK. The DPRK has an enormous army, but it is equipped with antiquated weapons. It also lacks fuel for its armored vehicles, tanks, and aircraft. On the contrary, the ROK has cutting-edge weaponry and sophisticated communications, intelligence, and electronic warfare capabilities.

Click on the adjacent link to download the full report.

This report is a part of a joint project on Reducing the Risk of Nuclear Weapon Use in Northeast Asia (NU-NEA) and has been cross-posted by the Nautilus Institutethe Research Center for Nuclear Weapons Abolition (RECNA), and the Panel on Peace and Security of North East Asia (PSNA).

About the Authors

James I. Matray, PhD, is emeritus professor of history at California State University, Chico, where he was History Department chair from 2002 to 2008. His publications focus on US-Korean relations after World War II.  He has written or edited nine books and publishing over fifty scholarly articles and book chapters. Author of The Reluctant Crusade: American Foreign Policy in Korea, 1941-1950, Matray’s latest major publication is Crisis in a Divided Korea:  A Chronology and Reference Guide (2016). He also is editor-in-chief of the Journal of American-East Asian Relations. His current research project investigates the Battles of Pork Chop Hill. 

Disclaimer: The views expressed in this report do not necessarily reflect the position of the Asia Pacific Leadership Network or any of its members.

Image: The U.S. National Archives

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