As technological innovation increasingly flows from the pri­vate rather than from the public sector, Kramer and Agachi propose engaging“new defenders beyond the traditional state-centric military model.” However, this involves a risk that the authors do not mention explicitly, namely that reli­ance on private actors diminishes government control and creates new dependencies. In that sense, Ukraine’s pro­nounced dependence on Elon Musk’s Starlink private-sector satellite network has created an additional vulnerability – on top of the uncertain prospect of continued US military aid. The relatively new concept of Multi-Domain Operations (MDO), which is currently the standard-bearer for the US Ar­my’s transformation, also emphasizes the relevance of tech­nology, cyber, and space. Another think-tank report, also co-authored by Franklin Kramer, stresses how implementing MDO would strengthen NATO’s deterrence and defense ca­pabilities in support of its regional plans. One specific step proposed in this report is that NATO and its member states should establish“integrated cyber and kinetic offense” as well as“assured provision in wartime of the private-sector space capabilities”(Kramer et al. 2024, p. 5). Interestingly, the issue of hybrid warfare or hybrid threats seems to have receded further into the background as com­pared with the 2014 to 2021 timeframe. Shortly after Russia’s annexation of Crimea in 2014, with the appearance of the “little green men,” hybrid warfare absorbed a lot of attention and triggered a substantial debate across the think-tank community in the US and other NATO countries. According to one prominent definition, hybrid warfare entails“use of military and non-military tools in an integrated campaign, designed to achieve surprise, seize the initiative and gain psychological as well as physical advantages”(quote from The Military Balance(2015) in Wither 2016, p. 76). In the aftermath of Crimea’s annexation, NATO allies de­cided that hybrid attacks on one member state could in principle trigger an Article 5 collective defense response. Eitvydas Bajarūnas, a high-ranking Lithuanian foreign af ­fairs official and visiting fellow at the Center for European Policy Analysis(CEPA) in Washington, complains that the Alliance still lacks a common understanding of when and how hybrid attacks could trigger Article 5. He urges NATO leaders to clarify this and proposes specific examples, such as severe cyberattacks that threaten to cripple essential in­frastructure(including power grids or financial systems). Other examples proposed as triggers to invoke Article 5 in ­clude“coordinated hybrid operations” as well as“multiple forms of attack”(disinformation, economic coercion, cy­ber-attacks)(Bajarūnas 2025). More recently, monitoring and protecting critical maritime infrastructure(pipelines, LNG terminals, undersea data and power cables) has also attracted more attention. One study by CSIS analysts proposes not only strengthening maritime forces – to include“traditional gray hull” as well as smaller vessels – but also working on national maritime strategies (Herdt and Zublic 2022, pp. 2–3). Societal resilience and “whole-of-society” approaches are another important as­pect in dealing with hybrid threats. In this context, new NATO members Finland and Sweden are seen as model cases from which other allies could and should learn. As Frida Rintakumpu and Veera Parko write for the German Marshall Fund,“both countries promote citizen involve­ment in security through education, communication, and participation in civil or military duties”(Rintakumpu and Parko 2024). Such activities prepare societies to deal better with“weaponized migration” and disinformation cam­paigns, as well as to cope with even more severe disrup­tions and emergencies. Finally, enhanced EU-NATO coop­eration is seen by some as critical when dealing with hy­brid threats. Monaghan and his colleagues view the creation in March 2023 of the“NATO-EU Task Force on Re ­silience of Critical Infrastructure” as a positive example (Monaghan et al. 2024, p. 14). Nuclear Deterrence and Arms Control The return of great power conflict and Russia’s onslaught against Ukraine in 2014 and again in 2022 led to a renais ­sance of nuclear deterrence in international security dis­course and practice. For NATO, too, nuclear weapons and nuclear deterrence have increased in significance. This trend was reinforced when Russian President Vladimir Putin re­peatedly issued nuclear threats in order to discourage NATO states from supporting Ukraine more openly. Nuclear shar­ing has become politically relevant again. Some NATO members, including Germany, finally took the decision to replace their aging fighter jets, earmarked for a nuclear mis ­sion, with fifth-generation F-35 jets. Meanwhile, the US has developed a new generation of air-delivered nuclear bombs, the B61-12, for NATO’s nuclear sharing arrangement. When it comes to nuclear deterrence, European NATO members are even more dependent on the US contribution than in the conventional sphere. While this nuclear de­pendency has been the subject of some debates in Europe ­an capitals, it has not really sparked a sense of urgency. Extended nuclear deterrence, which implies that Washing­ton is willing to defend its allies even with nuclear weap­ons, has been deeply rooted in the United States politically and institutionally. It has enjoyed broad support in the US Congress. Even the first Trump administration took specific steps to strengthen, rather than weaken, the credibility of extended nuclear deterrence. More recently, even the more radical approaches to burden-shifting in NATO do not question the US nuclear role in Europe or Asia. Accordingly, some think-tank contributions have focused on how to strengthen NATO defense and deterrence with a re­formed nuclear posture. The Alphen Group, which consists of leading security experts from the US(Stanley Sloan, John Allen, Ivo Daalder, Ben Hodges) as well as other allied na­tions, is among those that have addressed this issue. They suggest, inter alia, improving complementarity between con­ventional and nuclear forces and enhancing conventional Nuclear Deterrence and Arms Control 7