Work Stream 2: On-ramps For Future Arms Control

Penholders: Grant Christopher (VERTIC), Sharon Squassoni (Elliott School of International Affairs), Tong Zhao (Carnegie)

New START, which expired in February 2026, was the last arms control agreement limiting the numbers of nuclear weapons. Acknowledging the challenges in the current geopolitical climate, this work stream will consider options designed to enable or act as an ‘on-ramp’ for future agreements.

The next arms control agreement is likely to be substantially different to New START: a bilateral treaty that placed limits on delivery vehicles and number of warheads for long-range systems. New START included verification through national technical means and on-site inspections, transparency via data and telemetry exchanges and a dispute resolution mechanism through the Bilateral Consultative Commission. The likely states parties, weapons systems, domains and available verification technology may lead to a qualitatively different regime.

So-called, on-ramps would target where cooperation may be possible while acknowledging negotiating redlines. These on-ramps would address a subset of the following issues:

• Participating States. The United States has called for the inclusion of China which has resisted these calls arguing it does not have a nuclear force on the same level as the United States or Russia. Some experts have also argued for the inclusion of other states such as France and the United Kingdom.

• Types of system and numerical limits. Inclusion of systems not considered in New START and also addressing new and exotic nuclear-capable systems.

• Low yield nuclear tests. The United States reported in February 2026 that China conducted a nuclear test on 22 July 2020, that was not confirmed by the CTBTO. Prior to this questions have been raised about Russian testing activity.

• Missile defenses. This includes existing and proposed upgrades such as the Golden Dome.

• Space-based nuclear weapons. While already banned by the Outer Space Treaty, China tested a Fractional Orbital Bombardment System (FOBS) in 2021 and there has also been concern about the development of a new Russian system that would place a nuclear weapon in orbit.

• Emerging and disruptive technologies. This includes the use of AI for targeting and command and control, cyber-enabled left of launch attacks and other relevant interactions between these technologies and nuclear systems.