Why are nuclear delivery systems so important to the discussion of nonproliferation, and is the distinction between delivery systems from the weapons deserving of more attention in proliferation analyses?

Nuclear delivery systems are important to the discussion on nonproliferation because it takes three things to operationalize a nuclear weapon. Number one is bomb fuel or fissile material. This could be enriched uranium or plutonium. Number two is taking that enriched uranium or plutonium and putting it in the form of a bomb, what we call ‘weaponization.’ Number three is taking the bomb and putting it in a delivery vehicle. Without all three components you won't be able to have an effective nuclear force. Scholars have focused a lot on the first two. For example, we've looked at fissile material, how countries get them, develop them, acquire them from other countries. We've looked at how long it takes for countries to take their fissile material and weaponize them. The next step for us is to think about what countries do after that. How does a nuclear bomb that a country has built go from place A to place B? A colleague of mine recently made a comment that "a bomb doesn't have legs." It doesn't get to places by itself. It is important to look at what gives the bomb legs.

You have written about a zone of ambiguity and how it creates a permissive environment for development of nuclear delivery systems and also has important implications for state motivations in proliferation. Could you explain what is the zone of ambiguity and how it is employed by different actors?

The zone of ambiguity is essentially a permissive environment within the nuclear nonproliferation regime. That permissive environment has a few components. One is multipurpose technology, which refers to systems that can be used for different purposes. It could be a form of civilian technology with potential military purposes. Or it might be conventional military delivery technology that might also work for nuclear delivery. For example, the F-16 aircraft can drop both a conventional weapon and can be rewired to drop a nuclear weapon. Another element in the permissive environment is definitional obscurity, where the term nuclear weapon itself is not defined within the nuclear nonproliferation treaty, or the treaty on the prohibition of nuclear weapons. On one level, this is just baffling, but at another level is an interesting sort of puzzle. And the last component of the permissive environment is that nuclear delivery systems have been left out of the nuclear nonproliferation regime. This represents something states are able to take advantage of; it is a gap in the nonproliferation regime's ability to regulate technologies. How does this connect to state motivations? States might be motivated to proliferate for economic reasons, geopolitical reasons, or even prestige reasons. What enables them to follow through on those incentives, and either supply or be a recipient of nuclear delivery technology, is this permissive environment.

Based on proliferation history are there any regions of the world you see learning towards increased development of nuclear delivery systems?

I am concerned about a few areas of the world when it comes to the proliferation of nuclear weapons and associated nuclear delivery systems. One area I am concerned about is the Indo-Pacific, and the AUKUS deal between Australia, the UK, and the US. This deal is going to help Australia acquire nuclear-powered submarines. This agreement also includes provisions for the transfer of missile technology, advanced electronics, and cyber and AI-related capabilities to other allies and partners of the United States in the region. I'm concerned that a broader proliferation of some of these delivery technologies, including missile technology, hypersonic missile technology, and cruise missiles in the Indo-Pacific, will result in increased likelihood that nuclear latent countries in the region will move towards proliferation. There is some scholarship that suggests that some countries may build ballistic missiles first, which may encourage the eventual building of a nuclear weapon. This applies to South Korea, which has conducted submarine-launched ballistic missile tests. I am also concerned about Japan producing long-range missiles, as well as potentially a hypersonic ballistic missile. It is also concerning how the United States is helping Japan and Australia with cruise missiles and other missile technology. I was, of course, already concerned about North Korea, which is a nuclear weapons state. But I think, in general, the worry is that once you see a few of these countries developing and spreading these missile technologies that are ostensibly aimed towards China, a countermove may arise from China and its allies. At that point it would be very difficult to control the spread of this technology. The second region I am concerned about is Europe. We are seeing talks about the remilitarization of Europe, the greater expenditure of money on defense acquisitions, and increased interest by countries like Poland about nuclear weapons. Not only that, but delivery systems in the form of ballistic missiles are increasing, and NATO countries in Western Europe are pushing for this. All of these factors lend themselves to a greater diffusion of potential nuclear delivery capability.

India’s Prime Minister Modi recently attended the Shanghai Cooperation Organisation (SCO) summit in China, which many saw as a shift away from the U.S and towards China, a past adversary. How is this shift in alliances impacting nuclear delivery systems proliferation in China, India, and even Pakistan?

Prime Minister Modi attending the SCO meeting in China does not signal a large shift away from the US and towards China. Current developments between India and the US in the realm of trade policy have led India towards considering other potentially advantageous relationships in the international system. India has been a member of the SCO for a while now, but there is a reorientation taking place. India faces 50% tariffs from the US and therefore is deciding how to leverage other diplomatic relations to mitigate the effects this has on its own economy. I would also say that India-China relations, while they may be cordial right now, are still not necessarily friendly. The border dispute remains as one of the core issues that have been a thorn in India-China relations. The 2020 flare up that happened in the Galwan Valley is perhaps settled for now, but those territorial questions and competition over them remain. Bringing it back to nuclear delivery system proliferation, we have to look at it from the perspective of great power competition and how that's affecting India and Pakistan. The US-China nuclear competition has seen the US react to China's increasing arsenal with policies aimed towards an increased proliferation of strategic weapons, and vice versa. As China's reaction leads to an increase in their nuclear weapons, India will seek a capability with which it can pose a threat to China. As India potentially increases its nuclear delivery systems, Pakistan will do the same. This cascading effect is my main concern around how delivery systems may increase in today's political security driven competition context.

The 12-day war between Israel and Iran this summer ended when Donald Trump used American bombs to damage an Iranian nuclear facility. Given that the global nonproliferation system has no teeth, do you see governments increasingly defaulting to military strikes in nonproliferation efforts?

I wouldn't say that the nonproliferation system has no teeth. The nonproliferation regime has been fairly successful in preventing countries from developing a bomb or acquiring nuclear weapons.  Now, have there been cases, like Iran and North Korea where countries have either developed or gotten close to developing nuclear weapons despite having signed the NPT? Yes, but those are one or two cases in what has been a fairly successful regime. There is a question of whether the sanctions placed on Iran worked. One might argue that they did, and that is what brought Iran to the table of negotiations, which led to the Joint Comprehensive Plan of Action, or the “Iran Deal.” That deal, however, did not last because the United States withdrew in 2018. While one may argue sanctions have power in sparking negotiations, it is not clear that the bombing of Iranian nuclear facilities halted the nuclear program. Questions remain about what happened to preexisting enriched nuclear material, or even a secret fourth nuclear facility. Ultimately there have been questions, not only from the US intelligence community, but also from the International Atomic Energy Agency on the efficacy of bombing another country's nuclear facilities. It might slow down their ability to build the bomb, but it is not certain that it leads to the halting of a nuclear weapons program. I would hope that countries do not default to military strikes, because there are limited successes on that score. Additionally, if a country has a long-standing nuclear program, the best way to prevent a full-blown nuclear weapons program is to engage in negotiations.

What is the role of public opinion in nonproliferation efforts? Do you think public opinion has been and/or will continue to be a factor in the decisions of governments to advance or mitigate nuclear proliferation?

Public opinion has played an important role in nonproliferation efforts throughout the decades. Consider some of the anti-nuclear movements during the Cold War, particularly the nuclear freeze movement of the early 1980s in the United States, which brought a million people to Central Park in New York City on a single day. That movement led to legislative change and gave impetus to US negotiations with the Soviet Union on arms control treaties. Public opinion has played an important role in the humanitarian initiative, which led to the Treaty on the Prohibition of Nuclear Weapons, which more than 122 countries supported at the United Nations. Public opinion has been important in the decisions of certain countries and governments to address nuclear proliferation, leading towards nuclear disarmament. That said, in some nuclear countries, public opinion has had a comparatively smaller role to play due to the elite nature of nuclear decision making. Nuclear choices often take place at the highest levels of government, with minimal agency granted to the public. For example, if the United States or another country is deciding to increase its number of nuclear weapon systems, that choice is not subject to a public decision-making process. It is rare to even see public discourse about nuclear doctrine or strategic policy as it relates to nuclear weapons. In that sense, the role of public opinion can be a mixed bag. One hopes, however, that in democracy the public will have a greater role in nuclear decision making.