Why is New START important?
Following the collapse of the Intermediate-range Nuclear Forces treaty (INF), New START is the only remaining nuclear arms control treaty between the US and Russia.
This means that without it there would be no limits on numbers or the type of Russian and US deployed nuclear warheads. The limits set under New START are lower than those set under its predecessor, the Strategic Arms Reduction Treaty (START).
It is also important for maintaining some form of strategic arms control between Russia and the US. The treaty provides the US and Russia with mechanisms for transparency and confidence-building, for instance through regular biannual data exchanges, as well as measures for verification.
What is Russia able to do next after suspending participation?
President Vladimir Putin’s decision to suspend its participation could pave the way for Russia to increase the number of deployed warheads, delivery vehicles and launchers, potentially exceeding the limits placed on numbers under the new START.
Putin stated he would resume testing of nuclear weapons if the US resumed – Russia is a full state party to the nuclear Comprehensive Test Ban Treaty (CTBT) negotiated in 1996, as is the UK and France. The US has signed, as has China, but neither state has yet ratified the treaty.
Other countries required to ratify the treaty for it to enter into force include Egypt, India, Iran, Israel, North Korea, and Pakistan.
Although the US is modernizing its nuclear weapons forces, there is no need – or plan – for the US to test nuclear warheads, and it is the same for the UK and France.
Concerns are now rising that Russia could point to no-fissionable yield experiments – which are allowed under the treaty and which the US and other nuclear weapons possessors conduct primarily for safety purposes – and then falsely declare those to be nuclear weapons tests, thus paving the way for a narrative to justify the resumption of nuclear testing by Russia.
Conducting a nuclear weapons test would be seen clearly as a further step on the escalation scale towards nuclear use for Russia.
While inspections of nuclear weapons sites had not resumed since COVID-19, Russia’s suspension of its participation could result in the further halting of other transparency and verification measures under New START, including the regular mutual data exchanges between the US and Russia – for example on warhead numbers, locations, and technical information on weapons systems and their sites – which are conducted through the Bilateral Consultative Commission (BCC).
What is the difference between withdrawing from New START and ‘suspending’ participation?
In his speech, Putin announced the suspension of Russian participation in New START. While this does not mean Russia has formally withdrawn from the treaty, the suspension could enable Russia to continue preventing the US from inspecting its nuclear weapons sites and halt Russia’s participation in other obligations, such as the routine reporting and data exchanges on nuclear weapons as well as meetings of the BCC.
The decision to suspend participation rather than withdraw from the treaty means Russia retains the option to return to compliance at a later point. However, it is not yet clear under what conditions Russia would opt to return to compliance with the treaty, or whether this means the US will, in turn, suspend their own obligations.
The treaty text itself does not provide for a suspension of participation by parties to the treaty. However, the Vienna Convention on the Law of Treaties does address the mechanisms for suspension of participation in a treaty. Russia is a full state party to the Vienna Convention, but the US has remained a signatory without ratification since 1970.
There is a precedent of Russia suspending its membership in arms control treaties rather than withdrawing, which is when Russia suspended its participation in the original Treaty on Conventional Armed Forces in Europe (CFE) in 2007.
The US does not recognize Russia’s suspension of its participation in the CFE treaty, but this does not make a material difference to Russian actions.
What does the suspension mean for the wider international treaty regime?
Russia’s suspension of the New START could signal the end of strategic arms control between the two countries. There is now virtually no regular scheduled arms control communication between the two countries bilaterally – this is a dangerous position to be in, especially in times of crisis.
The suspension of New START further erodes limited recourse for communication between the two countries, by suspending information exchange and meetings of the BCC under the treaty.
This is likely to have wider implications for progress on nuclear non-proliferation under the Treaty on the Non-Proliferation of Nuclear Weapons (NPT), as well as the wider international security treaty regime.
Will this increase the nuclear threat or the likelihood of nuclear use?
New START provides both the US and Russia with a degree of transparency surrounding nuclear weapons systems. Without an avenue for regular data exchange and notification, and mechanisms for verification through mutual nuclear weapons site inspections, the risk of misperception or misunderstanding could increase and fuel uncertainty which could increases the perception of threat between Russia and the US.
What are Putin’s reasons for suspending Russia’s participation?
Putin and various members of his government have been linking the future of New START to the war in Ukraine rhetorically for several months now, threatening that Russia may not be willing to negotiate a follow-on treaty for when New START expires in Feb 2026 because of US support for Ukraine.
By announcing Russia’s suspension of the treaty in his main address on the anniversary of the invasion of Ukraine, Putin is sending a signal about Russia’s intent for the future.
Russia’s new hypersonic glide vehicle Avangard was already counted under New START and it is likely follow-on negotiations would have focused on some of Russia’s other hypersonic capabilities or other new nuclear systems.
Without the treaty, Russia might be less inhibited in its development of new nuclear systems.
Have both the US and Russia been compliant with the treaty until now?
Both the US and Russia have remained within the central limits of the treaty since its entry into force in 2011. Following the outbreak of COVID-19, both sides agreed to suspend in-person inspections due to restrictions on travel, and attempts to recommence in-person inspections in 2022 were unsuccessful.
In August 2022, Russia prevented US on-site inspections under New START and a November 2022 meeting of the BCC was called off by Russian officials. Russia has blamed both the ongoing COVID-19 pandemic and the sanctions burden on Russia as reasons for not wanting to resume inspections.