Beyond Ceasefire: Designing Credible Security Guarantees for Ukraine

Executive judgement

A ceasefire can interrupt violence; only a layered system combining Ukrainian defence capacity, persistent monitoring, pre-agreed support and long-term European commitment can reduce the risk of renewed aggression.

Key findings

• Ambiguous assurances invite incremental testing; credible guarantees define consultation and support mechanisms before a violation occurs.
• Monitoring must establish facts quickly enough to preserve political unity and deny advantages from engineered ambiguity.
• Ukraine's own resilient defence remains the first layer of deterrence and cannot be replaced by external promises.
• Guarantees require durable finance, industrial capacity and institutional ownership beyond the moment of negotiation.

The credibility problem

Security language is credible only when it changes an adversary's calculation before force is used. Political declarations that leave the trigger, timing and scale of support undefined may reassure temporarily while creating uncertainty during the first hours of a renewed crisis. A settlement therefore needs an architecture that links violations to consultation, emergency assistance and a prepared European response without pretending that every contingency can be automated.

Four mutually reinforcing layers

The first layer is Ukrainian national defence: trained forces, air defence, ammunition, logistics and a viable defence-industrial base. The second is monitoring and attribution through persistent technical observation and an agreed incident mechanism. The third is pre-arranged external support, including supply corridors and rapid consultation. The fourth is long-term cooperation that embeds training, industrial production and planning in European institutions.

Managing escalation and political cohesion

A guarantee must deter without creating incentives for miscalculation. Consultation arrangements should distinguish local incidents, sustained violations and major renewed attack. Governments should rehearse decision procedures and communicate enough about the architecture to strengthen deterrence while retaining operational discretion. Political cohesion is itself a capability: adversaries will test whether different capitals interpret the same event differently.

From agreement to endurance

The most difficult period begins after a document is signed. Monitoring missions need access and protection; industrial commitments need contracts; Ukrainian institutions need predictable finance; and European publics need evidence that arrangements reduce rather than defer risk. A formal annual review should assess military balance, compliance, readiness and the adequacy of response options.

Policy recommendations

1. Define violation categories, consultation triggers and emergency support channels in advance.
2. Establish an independent monitoring and attribution mechanism with protected technical access.
3. Fund multi-year Ukrainian air defence, ammunition, logistics and defence-industrial capacity.
4. Pre-position contracting and transport arrangements for rapid assistance.
5. Conduct annual political-military exercises of the guarantee architecture.

Indicators to watch

• Changes in force posture near agreed lines
• Restrictions on monitoring access
• Divergence among guarantor states
• Interruptions to long-term defence finance

Sources and method

This publication distinguishes verified institutional evidence from CERAX interpretation and forward-looking judgement. Principal public sources:

• European Council conclusions, 18 June 2026
• Coalition of the Willing, Paris Declaration