The idea of nuclear blackmail fascinated analysts early in the atomic age. It offered an especially vivid nightmare scenario: Some new Hitler demanding concessions but this time armed with nuclear weapons. Hitler’s cold-blooded demands backed with force made Britain and France back down in one crisis after another in the Rhineland, Austria, and Czechoslovakia. The first generation of strategists thought that a “nuclear Hitler” would present nearly impossible challenges to the West. Fortunately, such fears never materialized in the Cold War, as the superpowers lacked the daring drive of the Fuëhrer. They were much more conservative and cautious.

Still, it is a good time to analyze blackmail once again in the present. Many things have changed since the Cold War. When it comes to nuclear strategy, multipolarity is the order of the day in the second nuclear age. A nuclear context now blankets many more parts of the world, in East Asia, South Asia, and the Middle East. Whether or not nuclear blackmail is attempted, the nuclear context of any kind of blackmail surely does. Today nine countries have the bomb, so the opportunity for blackmail is greater for this reason alone. Further, the risk-avoiding behavior of the Cold War might not apply in a second nuclear age. The early strategists who worried about nuclear blackmail did not have the “curse of knowledge” of Cold War history. The cautious behavior of the first nuclear age may well repeat itself in the second. But then again, it might just be a historical relic. We simply do not know.

There is an important distinction that is needed to analyze the blackmail issue today between nuclear blackmail and blackmail in a nuclear context. The two are quite different. The latter — blackmail in a nuclear context — illuminates important issues that go unseen and unanalyzed when our framework focuses on straight out nuclear blackmail.

Nuclear blackmail is the threat to use atomic weapons to compel someone to take an action they do not wish to take. It contrasts with nuclear deterrence — the threat to retaliate to prevent an unwanted action. Let’s illustrate this with an imaginary example from the United States in the Vietnam War: Washington tells North Vietnam to get its armies out of South Vietnam or Hanoi will be leveled with a nuclear strike. This is nuclear blackmail. It would also be nuclear blackmail if the United States told Russia to vacate Ukraine in 30 days or suffer a military offensive using tactical nuclear weapons.

Blackmail in a nuclear context is different. It tries to compel someone to do something when one or more parties involved possess nuclear arms but when there’s no specific threat to use atomic weapons. Here’s another imaginary example: North Korea says that, if the United States continues to increase strategic pressure (with draconian sanctions, a blockade, roll up of overseas assets, jailing of all overseas North Korean officials, shutting down air space) to compel the Kim family regime to abandon its nuclear weapon program, Pyongyang will respond in ways that could easily lead to large scale war and that no options are off the table. The consequences, North Korean officials insist, will spill over to China, South Korea, and Japan. Here, both countries use blackmail threats. But neither the U.S. threat or the North Korean counter-threat is specific or explicit. Neither country says exactly what action will be taken, nor do they say that atomic weapons will be fired. Both sides will likely attempt to avoid looking like a calculating game theory strategist, using cynical power advantage to get what they want. Yet blackmail is still present on both sides. Washington threatens Pyongyang to give up its program, and Pyongyang threatens Washington to back off.

Or consider another example: Suppose China puts tactical nuclear weapons on its man-made islands in the South China Sea. Presumably this is to get the United States to back off from intrusive, provocative probes of the air and sea space around them. Suppose China says nothing, but the placement of weapons is purposefully leaked. Is this nuclear blackmail? Absent a specific demand from Beijing to Washington referencing their nuclear weapons, it is not.

Yet, clearly, the nuclear context matters a lot in all of these examples because all parties are likely to think about “where things might go” if the crisis intensifies. The distinction between “nuclear blackmail” and “blackmail in a nuclear context” is not some academic difference without a meaning. North Korea knows well that the United States has nuclear arms, and the United States knows the same about North Korea. Even if the United States has no plan or strategic intent, or even thought, about firing nuclear weapons, Pyongyang is likely to calculate that it does or at least that it might. Washington may well know that it is not going to fire these weapons, but it has a hard time convincing North Korea of this. The reverse holds too. Regardless of North Korean or Chinese strategies, plans, intent, or thinking, the United States will worry about a crisis in a different way because of nuclear weapons.

An important conclusion follows from this discussion: The mere existence of nuclear weapons changes the context, regardless of plans, strategic culture, or psychology. It may well be that narrow nuclear blackmail (“Give up Kashmir immediately or we’ll attack Mumbai with atomic weapons”) is not very likely anymore. But, the opportunities for blackmail in a nuclear context are greatly increased today.

Nuclear blackmail in the narrow sense offers what in economics is called a “narrow bracketing” of the problem. It is often said that nuclear blackmail does not work. It may well fail. But, a country that tries it can cause disaster. Hitler’s blackmail failed too. But, the “failure” led to millions of deaths in Europe in World War II.

Technology can make a difference, and this is important to underscore in the current era. Suppose North Korea gets a hydrogen bomb. Compared to the ten to 20 kiloton bombs it now has, a hydrogen bomb has an enormous lethal radius of destruction. If it landed on Seoul or Tokyo, it would kill at least hundreds of thousands of people. Today’s North Korean arsenal has the ability to kill in the thousands but not more. That North Korea could develop a hydrogen bomb is hardly implausible. China moved very quickly, taking only three years to go from an atomic to a hydrogen bomb in the 1960s. A North Korean hydrogen bomb would make a big difference. Imagine how Japan and South Korea would now view the already fraught missile tests that fly over them.

In addition, a nuclear accident in North Korea would have consequences many times greater with a hydrogen bomb, compared to their current arsenal of “small” atomic bombs. The radioactive fallout would be immense and likely blow on to South Korea and Japan.

Blackmail in a nuclear context widens the problem frame to operational and strategy issues as well. Enlarging the problem frame of nuclear blackmail brings in some important issues, namely the sequencing of blackmail and the object of the blackmail. Most narrow descriptions of nuclear blackmail use something like this abstract sequence of events:

There is peace, and this is interrupted by an attempted blackmail by a country to extort some gain or concession. This fits the outbreak sequence of World War II, as well as the hypothetical example of the United States threatening to strike North Korea, or Pakistan demanding that India get out of Kashmir.

But this is only one of many possible sequences. Some historical cases of blackmail fit this sequence:

For example, in order to end the Vietnam War, the United States blackmailed the government of South Vietnamo accept a peace negotiated behind their backs in Paris that allowed large numbers of North Vietnamese forces to stay in South Vietnam. Note here the sequence and object of the blackmail. It came as part of a U.S. effort to end the ongoing Vietnam War, and it was directed not at the enemy but against an ally. Washington made a “take it or leave it” offer to Saigon. If Saigon did not sign the peace agreement, all military aid would be terminated. If this is not blackmail, I do not know what is. The Korean war was also ended with enormous pressure on an ally. The United States pressured Syngman Rhee to accept a divided country and repatriate North Korean prisoners. Here again, there was an intrawar bargaining problem to terminate a conflict. Washington even had a plan to overthrow Rhee, Operation Ever-ready, to arrest and isolate him from to prevent his obstructing the armistice negotiations with the Communists. If we substitute “crisis” for “war” in the sequence diagram, Moscow sold out Fidel Castro by removing nuclear weapons to end the Cuban missile crisis. This was over the strenuous objections of Castro.

The sequence of peace-war-blackmail-termination offers a way to enlarge how we frame the subject of nuclear blackmail: as an intra-war bargaining device, and to ask a really interesting question, “Who is the object of the blackmail?” As the world goes into a new nuclear age, it is a useful exercise to stimulate and stretch our imaginations beyond the narrow framing of the blackmail issue. Major powers historically have put enormous pressure on their allies to accept deals they do not want. Adding a nuclear context to this, in my judgment, is likely to make this an even more significant possibility.

For example, suppose there is a crisis in North Korea or Pakistan that breaks out into a shooting war. One or two nuclear weapons are fired to signal that no one is bluffing. Further, suppose the damage is small because the weapons were fired on the territory of North Korea or Pakistan in defense against invaders. So, there already is a nuclear war underway, and the question arises of intra-war bargaining to end it. In this situation, both countries would still have a significant arsenal left over to threaten the attacker with considerable damage. The attacker would have a strong interest in avoiding this. In peacetime, it is common to overlook this kind of situation. This is because galactic abstractions, like deterrence theory, emphasize stopping a nuclear war before it starts. But what if a nuclear war has already broken out? Then, the details, tactics, and sequence of moves, etc. matter a lot. So does the object of blackmail (Is it the enemy? Or is at an ally?). Would the United States pressure South Korea not to take Pyongyang? Would China pressure Pakistan to stop the war? This is the reason that scenarios and war games are useful to uncover dangerous possibilities that were not recognized, like the importance of intra-war bargaining in a nuclear context. They also focus attention on issues that people have chosen to overlook to fit peacetime sentiments, like the importance of deterrence.

If there is a policy prescription that comes out of this discussion it is this: Calculated and cynical nuclear blackmail may not work and is extremely dangerous. But this too narrowly brackets the problem. A wider aperture is needed to understand blackmail, for there are multiple scenarios and possibilities that are overlooked in the narrow frame, especially as nuclear dynamics further darken some of the most unstable regions in the world. The opportunity for blackmail of any kind and for escalation to new and novel blackmail situations is growing.

Paul Bracken is professor of management and political science at Yale University. He is the author of The Second Nuclear Age, Strategy, Danger, and the New Power Politics (Times Books, 2012).

Image: U.S. Air Force photo by Master Sgt. Greg Steele