Even before the Russian invasion of Ukraine, addressing arms control policies in Europe and securing a follow-on agreement to the New Strategic Arms Reduction Treaty (New START) was a priority for the Biden administration. The United States has been particularly interested in potential limits on nonstrategic nuclear warheads (NSNW), which have never been subject to an arms control agreement.
 

Because Russia possesses an advantage in the number of such weapons, the U.S. Senate has insisted that negotiators include them in a future agreement, making their inclusion necessary if such an accord is to win Senate approval and ultimately be ratified by Washington. In the wake of Russian nuclear threats in the Ukraine conflict, such demands can only be expected to grow if and when U.S. and Russian negotiators return to the negotiating table.

Such an agreement will face major negotiating and implementation challenges—not only between Washington and Moscow, but also between Washington and NATO European allies. To stimulate this process, four NATO allies (Denmark, Germany, the Netherlands, and Norway) and one NATO partner (Sweden) funded a research team led by the James Martin Center for Nonproliferation Studies and former NATO Deputy Secretary General and New START lead negotiator Rose Gottemoeller. The research focused on the negotiating, policy, legal, and technical issues that allies will likely have to address to reach such an accord.
 

 

• NATO allies want to keep existing NSNW, and they want an agreement limiting Russian NSNW, and they expect to be substantively consulted before each round of negotiations. A decade ago, some US allies, such as Germany, appeared close to parting with the weapons because of public pressure despite considerable opposition within the alliance, particularly from newer allies with territory closer to Russian borders. While US Secretary of State Hillary Clinton managed to paper over these differences at the time, Russia’s behavior, including the 2014 annexation of Crimea and the 2022 invasion of Ukraine, has helped reinforce allied views that under the present circumstances, maintaining NATO’s current nuclear-sharing arrangements is the right approach. At the same time, the Ukraine invasion may further reinforce some allies’ doubts about the value of such agreements with Russia. All allies will need to be reassured that arms control and deterrence do not clash, but rather complement each other. US leadership and willingness to engage in substantive consultations will be crucial in maintaining unity. The allies’ experience in negotiating the INF Treaty and the Biden administration’s current close work with NATO on Ukraine provide useful models.
   
• Most of the Russian NSNW arsenal today is designed to support specific missions (as a backup to its emerging long-range conventional capability) and, from the perspective of the Russian military (particularly the Navy), will be tough to bargain away.
   
• Addressing NSNW will require overcoming operational and technical verification challenges that are made more difficult by issues of information security, definitions, and stockpile disparities. Nuclear-warhead design, composition, and capabilities are among the most closely held secrets of the nuclear-weapon states, and warhead movements pose the most sensitive nuclear-security concerns. Because parts of a nuclear warhead are replaced on a regular basis and warhead configurations can differ greatly, it could prove challenging to establish a universal definition of a warhead, and their size and mobility present major obstacles to accounting for and tracking individual warheads. US and Russian NSNW stockpiles also differ significantly in types and numbers.
   
• The experience in implementing the INF Treaty provides a useful starting point for considering how the new treaty might be implemented. Other agreements and inspection regimes to which many NATO allies are party also provide useful practical experience in preparing to host Russian inspectors. In advance of negotiations, allies should carry out a legal assessment to determine how domestic laws might need to be amended to carry out on-site inspections and other measures on their territory and a technical-capability assessment to determine how they might need to improve their staffing of national verification entities to implement an agreement.
   
• Allies also need to enhance the analytical and legal capabilities of their foreign and defense ministries when it comes to NSNW and arms control. In most countries, such expertis has withered in the decades since the end of the Cold War; newer allies were never involved in INF Treaty negotiations or implementation, even indirectly.
   
• US and allied research on verification measures for NSNW has largely focused on scientific and technical tools to conduct on-site inspections. The research team has developed an original and unique methodology for a data exchange employing historic stockpile data and taking advantage of past US-Russian cooperation and cryptography. This data exchange would serve as the critical backbone for other verification measures, no matter the type of warhead or the type of agreement (freeze, limitation, or reduction).
   
• Finally, sustained political engagement at the highest level will be essential to the success of any arms control initiative involving allies. If there is a lesson from the past three decades of arms control in the Euro-Atlantic region, it is that a penny-wise and pound-foolish approach has decimated the personnel and the intellectual investment in arms control. When arms control has been pursued in recent years, it often has been done in isolation from security policy, national strategy, and military planning, rendering it at best a curio within foreign ministries. Until this topic is taken seriously as an instrument of hard power, to reinforce deterrence as one of the most important ways nations seek to avoid or limit war, it will not find purchase on the rocky ground of great-power competition.