Since the birth of the deterrence theory, it has left a significant mark on the strategy of almost every country, and the reveal of the nuclear weapons gave it an incredible boost. However, the core logic of any deterrence strategy is rather clear, that state can achieve deterrence either by denial or by punishment. Deterrence by denial refers to a method that could lower the opponents' success rate, while the other one means to a capability with great retaliation. In some sense, deterrence by punishment is defensive because it does not include any measure of preemptive attacks, whereas deterrence by denial is a dangers spiral which clearly carries offensive characteristic. It is not hard to understand that, given the dramatic destruction power of nuclear weapons, deterrence by punishment was the most natural way regarding this subject, which means, in the old model of nuclear deterrence, nukes would be used literally because once it was fired, the deterrence actually failed already. As Bernard Brodie and Tomas Schilling argued, deterrence was all about bargaining and psychology.

They were right, at least during the cold war. History proved that even a then-mid-sized country like China could have quite a lot of autonomy facing a superpower like the Soviet or the U.S., as long as it had a certain level of survivability in its nuclear forces. In this context, many states or political entities began to pursue their own nuclear arsenal, such as the Republic of Korea (ROK), Israel, India, Pakistan, even Taiwan. Not all of them succeed obviously, and the reasons behind were not complicated as well: First, this was the cutting-edge technology and required a vast amount of resources; Second, states already processed nukes formed a privileged institution named Treaty on the Non-Proliferation of Nuclear Weapons(NPT) – pursuing nukes becomes a rogue behavior.

However, as we stepped into the 21st century, this old system trembled. First, the technological threshold was lowered; Furthermore, the facts more states becomes the de facto nuclear power also jeopardized the system. In 2004, Frank C. Zagare argued that the nuclear deterrence theory had a logical problem and his argument was echoed by many scholars such as Kissinger, Perry, George Schultz, and Sam Nunn. Nuclear weapons do not make the world a safer place, and the global nuclear arms-control has become increasingly unstable. ANBOUND also found this trend after years of tracking. Since 2006, we warn multiple times that because of the minimization of nuclear weapons and other technological breakthroughs, the possibility of the actual use of nukes has been increasing. We therefore argue that the old nuclear deterrence mode has already become outdated. We are stepping into a new phase of aggressive nuclear strategy. Nearly all nuclear states must consider the significance of the actual use of nukes in their defense strategy.

In detail, the number of nuclear states increases steadily. First, there is the United States, and in a rather short period, the Soviet Union, UK, became a nuclear power as well. In 1960s, all five standing members of the UN security council got access toward nukes; And the number continued to increase until 2017, when the Democratic People's Republic of Korea (DPRK) became a de facto nuclear state. Furthermore, the number of nukes, in general, also jumped noticeably. Nearly 20 countries have nuke-capable projecting vehicles. Most importantly, not all of these states are on the same side regarding its strategic stance, and even those in the same alliance system have conflicts of interests (for example, Israel and Saudi). In this context, it is hard to imagine that we could achieve a new nuclear balance in the future, and we will very likely to return to the age of Mutual-assured Destruction(MAD) mode.

So, what could be the future nuclear deterrence system in general? To figure out this question, we need first to understand the current possibilities. The first one lies between Iran and Israel, which mainly focus on maintaining military advantages in regional conflicts. The second one is the DPRK mode, where the nukes serve both as the bargaining chip and the core of the national defense. The third is the Indian-Pakistan mode, which processes lots of similarities to the first one, whereas the actual use of nukes is less possible. The final one is the triangle between China, Russia, and the U.S., which basically decides the global nuclear balance. To be noted, these four modes are interactive, and a change in one link could generate a chain-reaction to others. The most dangerous case is the DPRK. Nuclear weapons have both tactical and strategic means for Pyongyang, which means their nuclear doctrine must be offensive to be effective. In other words, the DPRK will never give up its nukes in the foreseeable future, the most realistic approach toward this issue was acknowledging their nukes and tried to contain it in a reasonable limit.

Another risk of the old nuclear deterrence, which is heavily relying on punishment, is that the collapse of this old system is simulative. Once the first shot was fired, there would be hardly a stop along the way. Moreover, the reveal of the tactical nuclear weapons further lowers the threshold because it is (relatively) cheaper, cleaner, and more valuable on the battlefield. Ocean clearly is the most dangers domain. There are already many analyses on the use of the tactical use in the modern maritime warfare, which is less likely to cause mass casualties on civilians, not even mentioning the wandering Ballistic missile submarine (SSBN) in oceans with god-knows-how-many nukes on it. If any kind of nukes was used in the maritime domain, the global economy could get a significant hit because of its reliance on the sea-trade lines.

In general, the previous deterrence mode that contains two major pillars is collapsing. The future nuclear deterrence will increasingly lean to the "denial" method, which means the nuclear strategy in general will become more and more aggressive. "Counter-force" will become the significant direction of future military technology. In this context, the possibility of actual use of nuclear weapons and the risk of global catastrophe will both jumped up. Future nuclear arm-control is facing enormous challenges currently.