Promises, Power, and Protection: The West’s Debate Over Security Guarantees for Ukraine

Monday, November 24, 2025, 11:00am – 12:00pm EST // 17:00 – 18:00 CET

Speaker: Iulian Romanyshyn, DAAD/AGI Research Fellow
Moderator: Jeff Rathke, President and Director of the Foreign & Security Policy Program, AGI

President Trump’s deal-making efforts to bring Ukraine and Russia to the negotiation table have so far not delivered. Even though a ceasefire—let alone a peace agreement—between Kyiv and Moscow remains elusive, accelerated diplomacy has raised the question of Ukraine’s long-term security, sharpening the link between the need to end the war and to construct a credible security guarantee. Ukrainian leaders have stressed that any meaningful security guarantees against Russian aggression need to be backed up by Western military force and political resolve. This, however, sits uneasily with the Trump administration’s approach, which has ruled out Ukraine’s membership in NATO, signaled its willingness to restore economic relations with Russia, and declared that Ukraine’s postwar security is the responsibility of European allies.

There is a great deal of political debate about a potential ceasefire or negotiated settlement. However, these debates have not elaborated on how to sustain the negotiated deal or what to do if Russia violates it by resuming aggression with renewed strength and bolstered resources. What capabilities does Ukraine need to effectively deny or punish another Russian invasion? What are the role and prospects of Western military presence in Ukraine? How does the credible commitment to Ukraine’s defense recalibrate transatlantic relations?

Dr. Iulian Romanyshyn is a senior fellow and lecturer at the Center for Advanced Security, Strategic and Integration Studies (CASSIS) at the University of Bonn. He is also the head of the scientific program at the Institute for International Cooperation, Technological Diplomacy and Communication (ICI) and an advisor at CMI – Martti Ahtisaari Peace Foundation. He previously held research and teaching positions at New York University, Maastricht University, Free University of Brussels, and European University Institute, as well as research fellowships at the NATO Defense College, the Academy of International Affairs NRW, and the Charlemagne Prize Academy. Iulian holds a PhD in political science from the IMT School for Advanced Studies Lucca, master’s and bachelor’s degrees from Maastricht University, College of Europe (Bruges), and the National University of Kyiv-Mohyla Academy.

Iulian’s research focuses on transatlantic security relations, EU security and defense policy, Black Sea security, and EU-Ukraine relations. He has published widely in many peer-reviewed journals, including the Journal of Common Market Studies, International Journal, Journal of European Integration, European Foreign Affairs Review, International Politics, and European Security, and contributed to a number of leading think tanks, including the Atlantic Council, Carnegie Europe, and the German Institute of Development and Sustainability. Iulian’s research has been acknowledged with the Global Strategy PhD Prize awarded by the Egmont Institute for International Relations and the European Security and Defence College.

This session will convene via Zoom. Please contact AGI Program Associate Mr. Jack Fornasiero at jfornasiero@aicgs.org with questions.


This event is supported by the DAAD with funds from the Federal Foreign Office.