Holding the line

Major General John Weidner recalls how his time at Los Alamos shaped his views of deterrence.

By J. Weston Phippen | April 2, 2024

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Major General John Weidner U.S. Army

In 2008, Major General John Weidner—then a lieutenant colonel in the U.S. Army—was stationed at Los Alamos National Laboratory. As a nuclear forensics and countering weapons of mass destruction (WMD) officer, also known as an FA52, Weidner was at Los Alamos to learn from the scientists and engineers who design nuclear weapons.

While at the Lab, Weidner recalls a conversation with a physicist who worked down the hall. “He was complaining about something at Los Alamos, and after several minutes, I interrupted him to ask why, given his frustration, he was still working at the Lab. Without missing a beat, he looked me dead in the eye and said he wanted to be of service to the nation and that working at Los Alamos was the best way he knew how to contribute.”

Weider says this type of patriotism is common across the nuclear security enterprise. “I have no doubt, none whatsoever, that this workforce will create and deliver the capabilities our nation needs to defend itself and our allies,” he says. “My nearly four years at Los Alamos provided me with an understanding of what it takes to create, sustain, and dismantle the nuclear stockpile—an incredible investment. Moreover, working at Los Alamos gave me the technical knowledge and practical experience to be successful in every one of my follow-on assignments.”

Today, Weidner is the chief of staff for the United Nations Command (UNC) and United States Forces Korea (USFK). National Security Science spoke to Weidner about how his time at Los Alamos informed his current position and helped shape his views on deterrence. 

This conversation has been edited for clarity and brevity. The views expressed are those of Major General Weidner and do not necessarily represent those of the U.S. Department of Defense.

You are stationed at U.S. Army Garrison Humphreys in South Korea, where you are the UNC and USFK chief of staff. What are your responsibilities?

The primary mission of the UNC is to support and enforce the armistice agreement that ended the hostilities of the Korean War. As the UNC chief of staff, I am the senior U.S. member on the UNC Military Armistice Commission (UNCMAC). I provide oversight of the process the UNCMAC uses to determine if an activity by either side violates the armistice agreement.

My other primary duty is to coordinate efforts across our personnel, intelligence, operations, logistics, plans, policy, information technology, and resource directorates within and between both commands.

How has the current geopolitical environment impacted your mission?

Russia, China, North Korea, Iran, and other state powers wish to overturn the rules-based international order that has served the free world so well for so long. For example, China is making claims to almost the entire South China Sea. Russia invaded Ukraine in complete disregard of the sovereignty of nations. North Korea is threatening war with the Republic of Korea and the United States. 

China has reportedly constructed more than 300 intercontinental ballistic missile silos in the past few years. Russia claims to have modernized more than 90 percent of its nuclear forces, and North Korea has enshrined nuclear weapons into its constitution and its leader has directed an exponential increase in nuclear warhead production.

For the first time, the United States will be challenged by two near-peer nuclear nations, as well as a third nuclear power that says it is increasing its nuclear capabilities and stockpile size. This is all occurring at a time when our nuclear forces are at their lowest level since the early 1950s, and all legacy nuclear weapons and delivery platforms have long outlived their design lifetimes.

The importance of the U.S. nuclear stockpile is to demonstrate that an adversary cannot escalate its way out of a failing conflict and that efforts to do so would cause its demise. Our nation must communicate and demonstrate this through well-trained, well-equipped conventional and strategic forces every day. 

How do you define deterrence?

Deterrence is the process of convincing someone not to do something. More specifically, it is decisively influencing perceptions regarding the costs and benefits of taking an action and not taking an action to convince someone that restraint is the best course. 

I believe the nature of deterrence endures. The character of deterrence, however, has evolved. For example, there are no widely agreed upon norms for behavior in space or cyberspace, and that is driving us to evolve our approach to strategic deterrence. 

How should the United States best prepare itself for the future?

Russia, China, and North Korea appear to be increasing the role of nuclear weapons in their national security strategies. Moreover, all those countries have used forms of nuclear coercion to obtain their national security objectives. In my opinion, the United States must evolve our nuclear stockpile to convince potential adversaries not to engage in conflict with the United States or our allies. First, we should move away from nuclear weapon life extension programs and begin the design of completely new nuclear weapons purpose-built for the threats, environments, and likely targets of the 21st century. Second, we should complete the planned modernization program of record and in doing so explore and incorporate smart, micro-, and nano-technologies into new nuclear weapon designs that provide real-time measurements that enable nuclear weapons with longer design lifetimes and reduced surveillance costs. These options would plug gaps that an adversary may see in our nuclear capabilities. They would also reassure our allies of our extended deterrence commitments.

A nation can have a reasoned debate on whether to develop a nuclear deterrent, but once the decision is made to develop that capability, there must be no debate on building, growing, and sustaining the capabilities and staff necessary to maintain that stockpile. The nation must also plan for and exercise strategic deterrence while in conventional conflict because the greatest risk of nuclear use will almost certainly stem from a regional conventional war. The conventional fight is unlikely to end with an adversary’s first use of a nuclear weapon. It will continue, and during that fight, the United States and our alliance must continue to deter the adversary from using nuclear weapons. 

How does Los Alamos help in this mission? 

Los Alamos and the other labs, plants, and sites of the National Nuclear Security Administration are foundational to the vision I described. We need to unleash the talent, creativity, ingenuity, and dedication of our workforce on the problem. 

The national labs are helping leaders within the Department of Defense understand the threats we currently and are likely to face in the near-term. The labs can offer options and capabilities at the best possible value. This has been invaluable and educational. For example, the labs have some of the best nuclear weapon effects models. Those models are helping military and civilian leaders understand the outputs and effects of nuclear weapons. 

Speaking of effects, people may not know the Army has nuclear specialists, the FA52s. What is their unique role?

FA52 officers are the primary advisors to senior leaders on the effects of nuclear weapons. We are assigned in various capacities across the Department of Defense, as well as the Department of Energy and the Department of State. Some FA52s also support the intelligence community by providing in-depth analyses and assessments of emerging nuclear threats.

Tell us about your assignment at Los Alamos.

Los Alamos was the longest assignment of my career—nearly four years from fall 2008 to summer 2012—and one of my most enjoyable. I supported weapon physics studies on the W78 warhead and did medical isotope production experiments to complete my PhD. I also helped create an electronic database of U.S. nuclear tests, participated in many national technical nuclear forensic analyses and exercises, and made several cooperative threat reduction trips to the former Soviet nuclear test site at Semipalatinsk, Kazakhstan.

I cannot overstate the importance of my assignment at Los Alamos. In my current role, I have been involved in the Nuclear Consultative Group meetings between senior Republic of Korea and U.S. national security members. My Los Alamos experience has informed my discussions with both the Republic of Korea government and military and helped me articulate the outputs and effects of nuclear weapons as well as options to manage the consequences of nuclear use. 

Given the increasing role of nuclear weapons in the nuclear security strategies of North Korea and other countries, how do you see the role of the FA52 evolving?

Among other things, FA52s will play key roles in advising military and civilian leaders about the effects of nuclear weapons and nuclear-related policy. In my experience, most leaders overestimate the effects of nuclear weapons, which may cause them to underestimate the likelihood of adversary nuclear use. 

I believe the most likely scenario for adversary first use of a nuclear weapon is in a conventional conflict they are losing. Should an adversary use a nuclear weapon in that case, the conventional war would continue. Therefore, it is important for U.S. military forces to understand how to operate in and through a nuclear environment created by an adversary. 

That may seem like an obvious statement, but almost all our leaders have lived their entire professional careers in an environment where adversary nuclear use was almost unthinkable. The United States has not been in a conflict where it had to worry about being out-escalated since World War II. 

With that in mind, it’s imperative that the United States and our allies develop a vision for how to go to war against a near-peer adversary. This includes an approach for how to mobilize a nation for war and how to integrate all elements of national power. In this way, our nation and our network of allies and partners will be best prepared to deter conflict and, if necessary, prevail in conflict. FA52s will be central to all of this.  ★

Meet another FA52 here.