Pressing the Button: How Nuclear-Armed Countries Plan to Launch Armageddon (And What to Do About the U.S.)


What would happen if the president of the U.S.A. went stark-raving mad?”

That question appeared on the cover of Fletcher Knebel’s bestselling 1965 novel, Night of Camp David. Knebel, who also wrote Seven Days in May, described a president succumbing to paranoia as those around him struggled to keep him from starting a nuclear war. For obvious reasons, the book was re-released in 2018 in a new edition.

The presidency of Donald Trump has renewed a lingering debate about how much of the terrible responsibility to inflict large-scale nuclear destruction nuclear-armed countries should invest in a single person. The question is not only about Trump, of course. He is a member of a club that also includes Russia’s Vladimir Putin, China’s Xi Jinping and North Korea’s Kim Jong Un — “Rocketman” himself. It is a club that is far more exclusive than the Mar-a-Lago.

The terms of this debate are well-known and relate to the specific requirements of nuclear deterrence. On the one hand, there is a broad desire to retain political control over the use of nuclear weapons and to ensure that nuclear weapons are never used by accident or by an unauthorized person. On the other hand, it is typically thought that the credibility of deterrence relies on the certainty of retaliation under all circumstances, even in difficult ones, such as in response to a surprise attack.

These twin goals are in tension, a situation that Peter Feaver famously termed the “always/never” dilemma — the weapons should “always” launch when ordered by a legitimate authority, but “never” if no legal order has been given. Each nuclear-armed state has struck a slightly different balance at different points in time, with states shifting “back and forth between delegative and assertive postures” depending on the importance placed on the urgency of response and the general state of civil-military relations and domestic politics. A preference for “always” — certainty that any lawful launch order will be executed — may lead a state to accept a greater risk that nuclear weapons could be used without proper authorization. The preference for “always” could, in extreme cases, lead to so-called “dead hand” systems that would ensure the launch of nuclear-armed missiles even if political leaders were dead.

A common procedure to manage the always/never dilemma is to require two or more persons at various links in the chain of command to agree on a step involving nuclear weapons (the so-called “two-man” rule.) The two-person rule may differ greatly in practice across states. In some cases, it may be a physical requirement for at least two people to execute any nuclear-related procedure, which may include two simultaneous moves or gestures, or the insertion of two codes (or separate parts of a single code — a “half dollar bill”). It may be the legally mandated presence, alongside the authority giving the order, of an authenticating, controlling, or verifying authority for any nuclear-related procedure (possibly as a separate chain, with reporting upward along the line). It may also be the existence of two different chains of command, with separate orders given all along the line: for instance, one for launchers and one for warheads.

“Code” generally refers to a short alphanumeric series (say, four to twelve letters or numbers) that can be read or memorized. However, codes may also be more complex signals, communicated only by electronic means. Codes may serve different functions. “Authentication codes” prove that the person giving the instruction is legally entitled to do so. “Enabling codes” unlock missiles or, in the case of permissive action links, warheads.

While the two-person rule is common throughout the chain of command, several nuclear-armed countries choose to concentrate the legal authority to order the use of nuclear weapons in the hands of a single political leader. Here is a key distinction: Authority is not the same thing as ability. The former is a legal or political concept, the second a physical and military one. In most if not all nuclear-armed countries the authority to use nuclear weapons is held at a much higher level than the ability to use those weapons. What the two-person rule accomplishes is to divide the ability to take an action among multiple persons, thereby increasing the likelihood that nuclear weapons will only be used on the order of the appropriate authority. The election of Donald Trump has renewed debate over the wisdom of this arrangement.

The fundamental issue, however, is not merely the question of Trump himself. Many nuclear-armed states are expanding the number and type of nuclear weapons they possess, introducing systems that complicate the always/never dilemma for command and control. Several countries are deploying nuclear-armed ballistic missile submarines for the first time, for example. Moreover, new developments in communications and encryption technologies may improve the security of nuclear command and control, or they may introduce new vulnerabilities such as the possibility of hacking.

In a recent study for the Middlebury Institute of International Studies at Monterey, we sought to address five questions for each of the nine known nuclear-armed states: Who has the legal authority to use nuclear weapons and on what grounds? How would the decision to use nuclear weapons be taken and how would that decision, in the form of an order, be transmitted? What are the procedures designed to ensure political control? Have any states pre-delegated the authority to use nuclear weapons, particularly to military commanders in the field in specific circumstances? And, what would happen if the legitimate authority was incapacitated?

There is no single national model for authorizing the use of nuclear weapons, although almost all countries claim to have some variant of the two-person rule. Many countries, though not the United States, assign an important role to a civilian defense chief or the head of a military general staff (details are often unclear), and some have set up “devolution” procedures that hand down launch authority if something happens to the president or prime minister: such authority is automatically “devolved” to another institution (e.g. a government minister) even if constitutional succession is not permitted by circumstances.

There are, however, important differences. Parliamentary-type governments where political authority to command the armed forces (and thus use nuclear weapons) is delegated to a prime minister tend to emphasize collective decision-making. The decision to launch a nuclear strike is not expected to be a purely individual one — even if the prime minister has that authority in a legal sense. The United Kingdom, India, Pakistan, and Israel operate under this kind of system.

Presidential systems, where executive authority clearly rests in the hands of one single person elected by the people, tend to treat the decision to order the use of nuclear weapons as an individual one, with the ability to give such an order becoming a kind of metaphor for the power of the president. In this regard, France and Russia appear to be the closest models to the United States. China’s nuclear decision-making is thought to be more collective, although that may no longer be true in the era of Xi Jinping.

Even in presidential systems, it is too simplistic to claim that one single person’s orders are enough to launch a nuclear strike. This is often true legally but of course an entire chain of command is needed to execute such an order. From the officer holding the “football” to the officers in launch units with keys or combinations to safes, the chain of command and process of authentication always requires the positive participation of a number of human decision-makers. There may be automated processes along the chain of command, but there is nothing automatic in the execution of a launch order. Even the Russian system Perimetr (sometimes inappropriately confused with the “Dead Hand,” a Soviet-era concept which was never implemented) must be switched on and a person remains in the decision-making loop. Moreover, the presence of human decision-makers throughout the chain of command is usually augmented with two-person rules. With the exception of North Korea — about which information is unsurprisingly thin — all nuclear-capable countries claim to require two people at certain points in the nuclear use process, albeit in various ways.

The presence of multiple human decision-makers in the chain of command raises the possibility that individuals would resist an unlawful order to use nuclear weapons in the case of a completely out-of-the-blue nuclear strike. For example, there are some reports that captains of U.S. ballistic missile submarines are expected to make communications contact in the event of an unexpected launch order that seems out of place or character. At least one captain has indicated that, in the event of a peacetime launch order, he would insist on confirmation and a justification.



There are, however, legitimate questions that might be asked about such arrangements, particularly the idea that troops in the line of duty might resist an unlawful order. Good order and discipline within military organizations mean that in the vast majority of cases, an order to use nuclear weapons would be followed. In states where the authority is conferred upon a single person, even a completely irrational order might be followed if it occurred in the midst of a crisis. And there are questions of legitimacy: In many cases, there is a process to devolve authority if top leaders are incapacitated, eventually to unelected officials. (In the United States, succession eventually devolves to the eligible heads of federal executive departments in the cabinet.)

There is no obvious way to reconcile all the above-mentioned imperatives such as credibility, legitimacy, efficiency, safety, and security. At the same time, whatever balance is struck at any given moment must be regularly reassessed. The great George Quester, testifying during the first hearings on presidential control of nuclear weapons in 1976, outlined the important questions that continue to shape the public debate: “Can we achieve tighter control over a President without sacrificing the same important credibilities in deterrence? Can we do so without sacrificing controls over the military? Have we perhaps left the President too uncontrolled in earlier days, in the process of balancing deterrence and the control of the military?” More than 40 years later, we think the answer to each of these questions for the United States is a qualified “yes.”

Neither of us is terribly convinced by recent proposals from Congress to insert itself into the process and usurp, in part, the president’s authority to order a nuclear strike. The president is the commander in chief. Once Congress appropriates the funds for military forces, it has little to say about how these forces might be used beyond the power to declare war. Congress has consistently avoided even this responsibility, as the failure to revise the 2001 Authorization for the Use of Military Force demonstrates.

Nevertheless, Congress could attempt to compel the president, time and circumstances permitting, to confer with at least the vice president, secretary of defense, and the chairman of the Joint Chiefs of Staff regarding any decision to use nuclear weapons and especially a decision to initiate the use of nuclear weapons. These individuals need not be given a veto in the process, but each must be offered a chance to give advice.

There would be little downside to such an approach. In our work, we find no evidence that states requiring a collective decision are seen by potential adversaries as less credible than single-person models that favor speed and legitimacy. In NATO, the collective use of nuclear weapons requires consensus of all members of the North Atlantic Council, although the United States, the United Kingdom, and France retain the ability to use nuclear weapons on their own. Whatever doubts we might have about the certainty of retaliation in the most extreme scenarios, those doubts pale in comparison to the ones we have about the wisdom of allowing a single individual unfettered authority to order the use of nuclear weapons.



Jeffrey Lewis is a scholar at the Middlebury Institute of International Studies at Monterey. 

Bruno Tertrais is Deputy Director at the Fondation pour la recherche stratégique in Paris.


Image: Steve Jurvetson