Only a strong LIO can prevent CBW and nuclear terror.

At the global level, it is difficult to counteract nationalist populists’ influence. Multilateral regimes may be able to withstand temporary problems caused by individual noncompliant states. Some may hope that populism will simply wither away and that they can wait the populists out. But, as argued above, the underlying assumption that populism is a passing phenomenon is questionable.

The Alliance for Multilateralism, which is an “informal network of countries united in their conviction that a rules-based multilateral order is the only reliable guarantee for international stability and peace and that our common challenges can only be solved through cooperation,”Footnote111 can be understood as a way to balance and constrain the destructive policies of nationalist populists at the global level. Yet it is not clear what shared interests, apart from opposing nationalist populism, these multilateralists have.

In the meantime, multilateralists attempt to maintain ties by cooperating with the populists on issues that are deemed noncontentious. In the nuclear area, this relates, for example, to nuclear security and the prevention of terrorist attacks with chemical, biological, nuclear, or radiological weapons through better preparedness and improved resilience.

The challenge is complex. It arises from within the multilateral system but has been created by the anti-multilateralist positions of the nationalist-populist leaders of great powers. If these countries are permanent members of the UN Security Council, the problem is even more difficult to tackle.

The rise of nationalist populism is taking place in the context of an erosion of democracy, a rise of authoritarianism, and the proclaimed demise of the liberal international order. Populism is simultaneously a cause and a symptom of underlying disintegration processes often framed as democratic backsliding and the end of the US-led liberal order. Effective responses to counter nationalist-populist policies and arguments have to be proactive. States and societies cannot simply wait for nationalist populists to fail as a result of the contradictions that their policies produce. Political systems have to address the root causes of populism in order to make them more resilient to the threats populists pose and to counterbalance the risky behavior in which populists tend to engage. This is true particularly for the nuclear order, where the risks are existential.

In describing the dangers associated with the rise of nationalist populism to power in nuclear-weapon states, we have used illustrative examples to make our arguments. Future research could draw on more empirical data and hopefully describe the specifics of nationalist populists’ policies in a more comprehensive and systematic manner. While the nationalist-populist leaders described here share specific ideas and a policy style, they differ in important ways. Analyzing the different characteristics and strategies of nationalist-populist foreign and defense policy, and particularly nuclear policies, in a more systematic way would be useful to identify the ways in which these actors talk about nuclear weapons and make decisions. It would also be worthwhile to analyze in detail how nationalist-populist nuclear-weapon policies interact with the trends in the nuclear order that have increased nuclear risks over the last 30 years—the shift to a multipolar order, the growing importance of subnational actors, the weakening of strategic stability through novel technologies. We are afraid that the bleak picture we have painted would then become even darker.