[News in War History] The Crucial Difference Between Similar Yet Distinct 'Nuclear Umbrella' and 'Nuclear Sharing'

Concept Born Amid Nuclear War Risks After WWII
France Chooses Independent Nuclear Armament Over US Nuclear Umbrella
Nuclear Sharing Could Become Risky During Allied Conflicts

Editor's Note[News in War History] is a content series created to provide multifaceted perspectives on war and conflict news from around the world as it unfolds moment by moment. Through 'News,' we first examine the current situation; through 'History,' we analyze the hidden meanings behind the news; and we also offer 'Implications' for the near future. We visit you every Sunday and plan to publish a book after 40 episodes.

The Korea-US summit, which attracted great attention not only in our country but worldwide, has come to a conclusion for now. The biggest keyword that emerged from this summit was undoubtedly the 'nuclear umbrella.' Following the so-called 'Washington Declaration' announced after the summit, the United States declared that it will provide a significantly strengthened nuclear umbrella to South Korea, prompting other US allies, including the North Atlantic Treaty Organization (NATO), to remain vigilant about future changes in the security environment.

Some voices express concern that despite the strengthened nuclear umbrella, the security anxieties triggered by the Ukraine war may accelerate the pace of nuclear armament among various countries. There is a forecast that the nuclear weapons development frenzy seen in countries like the United Kingdom and France during the Cold War period after World War II, when they faced the threat of Soviet nuclear attacks, could resurface.

In February, the U.S. Air Force conducted a test launch of the Minuteman III intercontinental ballistic missile (ICBM) at Vandenberg Air Force Base in California. [Image source: U.S. Air Force]

On the other hand, there is a growing call for US allies across Asia to establish defense systems based on nuclear sharing, similar to NATO countries in Europe. This is especially because, in the context of Northeast Asia, where nuclear threats from neighboring countries such as North Korea, China, and Russia are increasing, relying solely on the US nuclear umbrella is considered insufficient.

In this edition, we will explore the history of nuclear deterrence strategies such as the nuclear umbrella and nuclear sharing surrounding the security and future of Northeast Asia, and discuss the meanings of nuclear umbrella and nuclear sharing, which are similar yet distinct concepts.

◆News: Biden Reaffirms Nuclear Umbrella Provision to South Korea... South Korea Renounces Independent Nuclear Armament

[Image source=Reuters Yonhap News]

Let's start with the news. On the 26th of last month, President Yoon Suk-yeol and US President Joe Biden agreed to establish a Korea-US 'Nuclear Consultative Group (NCG)' during their summit at the White House, and announced this through the Washington Declaration. The Nuclear Consultative Group is a consultative body designed to share information related to the US nuclear umbrella provision against North Korea's nuclear threats and to discuss plans and execution related to nuclear force operations with South Korea's participation.

This declaration has raised expectations that the nuclear umbrella the US has promised to provide to its ally South Korea will be significantly strengthened. The nuclear umbrella refers to the promise by a nuclear-armed country to provide nuclear forces to defend an ally without nuclear weapons in case of emergency, thereby exerting strategic deterrence against hostile countries posing nuclear threats. This is also known as the 'extended nuclear deterrence (END)' strategy.

The US currently claims to provide a nuclear umbrella not only to NATO allies in Europe but also to non-NATO allies such as South Korea, Japan, and Australia. The concept of the nuclear umbrella emerged in the 1960s as the US repeatedly pledged diplomatic nuclear security assurances to its allies who had renounced independent nuclear armament by joining the Nuclear Non-Proliferation Treaty (NPT), thereby alleviating their security concerns.

Conceptual diagram of the U.S. nuclear umbrella. [Image source= U.S. Nuclear Threat Initiative (NTI)]

During the summit, President Yoon also drew attention by mentioning public opinion in South Korea favoring independent nuclear armament. On the 28th (local time), during a dialogue with Joseph Nye, Harvard University Distinguished Service Professor, and the audience at Harvard University, President Yoon stated, "There is public opinion in our country that we should have independent nuclear armament," and emphasized, "South Korea has the technological foundation to develop nuclear weapons within a short period, even within a year, if it decides to do so."

However, President Yoon also noted, "Nuclear weapons are not just a matter of technology; there are complex political and economic equations related to nuclear weapons," and added, "The Washington Declaration includes not only the obligations of the US administration but also South Korea's obligation to respect the Nuclear Non-Proliferation Treaty (NPT) and not to pursue independent nuclear development."

Nevertheless, discussions will continue between the two countries and among the US and its allies regarding the form the strengthened nuclear umbrella will take. While some interpret that the nuclear umbrella provision to South Korea might resemble NATO-style nuclear sharing, the US government has drawn a line, stating it is not a nuclear sharing arrangement, sparking controversy. The debate over the interpretation of these two terms, which appear similar but have significant strategic and diplomatic differences, is expected to continue.

◆History 1: The Concept of 'Nuclear Umbrella' Emerging in UK and France's Independent Nuclear Development Post-World War II

Nuclear test conducted in 1971 in the Mururoa Atoll area of French Polynesia.

First, let's take a closer look at the concept of the nuclear umbrella. According to the US security research organization Nuclear Threat Initiative (NTI), the term 'nuclear umbrella' officially appeared in the international community through the concept of 'Positive Security Assurance (PSA)' established by United Nations Security Council Resolution 255 in 1968.

This concept means that nuclear-armed countries protect the nuclear security of their non-nuclear allies. In the 1960s, it mainly appeared as the US protecting its allies from the Soviet threat. In other words, if a hostile country launches a nuclear attack on an ally, the US promises to respond with a nuclear attack to neutralize the enemy.

The emergence of this concept is intertwined with France's nuclear development history after World War II. France, which was occupied by Nazi Germany during World War II and later regained independence, did not possess a single nuclear weapon, unlike the US and UK, which had already developed nuclear weapons. During the early Cold War, as the Soviet nuclear threat intensified, then French President Charles de Gaulle was very uneasy about the US's offer to provide a nuclear umbrella.

De Gaulle, who became president of the French Fifth Republic in 1958, experienced diplomatic humiliation when France was not a leading country in NATO's founding because it was not a nuclear-armed country. He emphasized the need for independent nuclear armament, asking, "Would the US really sacrifice New York for Paris?" In 1960, France succeeded in independent nuclear development and became a nuclear-armed country.

Although France's nuclear forces were weaker compared to the Soviet Union at the time, the existence of nuclear weapons capable of retaliating and devastating parts of the Soviet territory served as a deterrent against Soviet nuclear strategy. This strategy was called 'deterrence by the weak of the strong' and became the basic security strategy for countries pursuing nuclear development thereafter.

However, this strategy risked triggering an unlimited arms race encouraging nuclear armament by all countries worldwide. During the Vietnam War, considered a proxy war between the free world and the communist bloc, concerns about the outbreak of World War III grew. To prevent this, the concept of the nuclear umbrella provided by the US to its allies officially emerged in the international community.

◆History 2: NATO-Style Nuclear Sharing Controversy During the Greece-Turkey Conflict

[Image source: North Atlantic Treaty Organization (NATO) website]

Along with the emergence of the nuclear umbrella concept, a more strengthened nuclear umbrella policy introduced in Europe during the Cold War was the nuclear sharing program. In response to security requests from non-nuclear European countries, the US deployed its nuclear weapons directly to some European countries and, in case of emergency, these weapons could be used under the final approval of the US president.

Currently, approximately 240 US tactical nuclear weapons are reportedly deployed in five NATO member countries: Germany, Belgium, the Netherlands, Italy, and T?rkiye (Turkey). During peacetime, these nuclear weapons are stationed in allied countries without nuclear weapons and are managed by the US Air Force or Army depending on the characteristics of the nuclear forces. The final launch authority rests with the US president. Some tactical nuclear weapons are mounted on allied combat aircraft during wartime and operated jointly.

From the perspective of non-nuclear countries, having nuclear weapons deployed on their soil that can be used in actual combat ensures a definite nuclear deterrent against hostile countries. However, NATO-style nuclear sharing has also led to dangerous situations. In 1963, Greece and T?rkiye, both NATO members and holders of US nuclear weapons under nuclear sharing, engaged in armed conflict over the Cyprus dispute.

As the conflict escalated, both countries attempted to seize control of the US tactical nuclear weapons deployed on their soil under nuclear sharing, nearly triggering a nuclear war between NATO allies. Subsequently, US tactical nuclear weapons deployed overseas under nuclear sharing were equipped with 'Permissive Action Link (PAL)' devices, requiring the US president's final approval before use.

◆Implication: Increasing Number of Countries Seeking Independent Nuclear Development Amid Rising Military Tensions

[Image source=Yonhap News]

However, as global security risks rise due to Russia's invasion of Ukraine and China's threats in the Taiwan Strait, many countries engulfed in fears of large-scale nuclear war are increasingly voicing support for independent nuclear development rather than relying on nuclear umbrellas or nuclear sharing.

Even if security is guaranteed through nuclear umbrellas and nuclear sharing, there is significant anxiety about entrusting a nation's fate to another country. Particularly, countries with the economic capacity for nuclear armament, such as South Korea and Japan, as well as Middle Eastern countries like Saudi Arabia, are showing great interest in independent nuclear armament, raising concerns about nuclear proliferation.

Public opinion on independent nuclear armament varies by country. Since it is a project that consumes enormous resources for development, weapon production, and maintenance costs, it is a difficult decision to make lightly. Until a peaceful era returns, like the early 1990s after the Cold War collapse when global security risks significantly decreased, debates surrounding independent nuclear armament are expected to continue.