Contrary to much of the public debate, U.S. president-elect Donald Trump will not usher in a new era for European security. Instead, his victory only ratifies a shift in U.S. priorities that has been a generation in coming—and that European leaders have been slow to accept and respond to. Throughout the Cold War and the decades that followed, the U.S. military was Europe’s ultimate protector. Today, Washington remains a partner but will no longer guarantee European security. Europeans must be prepared to defend their countries and their continent, as multiple U.S. presidents have warned.

There is no single answer to the question of who will fill the space left by the reduction of U.S. security commitments, military presence, and capabilities. With luck and good leadership, NATO will be able to erect and rely on a stronger European pillar. The European Union will mobilize funds needed to expand defense production. But European countries will need to do more than delegate to their collective institutions. They will need to work creatively and entrepreneurially among themselves in smaller, nimbler coalitions.

The Joint Expeditionary Force (JEF) is one such grouping. Originally conceived by the UK in 2012 and blessed by NATO allies at the Wales Summit in 2014, the JEF now includes Denmark, Estonia, Finland, Iceland, Latvia, Lithuania, the Netherlands, Norway, Sweden, and the UK. Designed to create a pool of high readiness and adaptable forces, the JEF increases the military interoperability of its members through regular exercises and patrols. It has been particularly active in the protection of Baltic undersea infrastructure. When Sweden and Finland were not NATO members, one function of the JEF was as an operational bridge to these close NATO partners. Now that all of northeastern Europe is part of NATO, questions have arisen about the JEF’s raison d’etre and future.

Instead, leaders should adapt the JEF to meet the moment. At the next meeting of JEF heads of government in Estonia later this month, members should confirm their intention to maintain the JEF and upgrade its focus and operations. Here are six ideas for heads of government to consider implementing, some of which were spurred by discussions we chaired at a recent meeting of Carnegie’s Baltic Sea Region Security Initiative.

Clarify the JEF’s mandate. Rather than seeing the JEF as a mechanism to manage security challenges that don’t rise to the threshold of triggering NATO action, members could embrace a more active framing of the JEF’s purpose: a collection of rapid response capabilities that can be deployed at early signs of a crisis that threatens to become a conflict. Hand-wringing is too often the typical response in this liminal period, and JEF leaders could send a signal to Russia and to each other that they intend to respond actively to provocations and hybrid actions.

Set an ambitious program of exercises. JEF members can demonstrate NATO’s capabilities in northeast Europe and signal their commitment to deny Russian (and Chinese) moves in the region, including, but not limited to, the threat to undersea infrastructure. More, and more expansive, exercises would prepare the JEF for its future deployment in crisis and serve as a deterrence measure against hybrid attacks. The rapid and unbureaucratic decisionmaking that is the inherent promise of a minilateral grouping like the JEF should be a focus of these exercises.

Seek NATO endorsement. JEF members should agree to work together to get all NATO allies to reconfirm the value and purpose of the JEF at the next NATO summit in the Netherlands in June. In the future, the JEF should become integrated in NATO’s operational plans. For now, the summit communiqué should make clear that the JEF is a mechanism for supporting NATO’s broader strategic approach and contributes to, rather than undermines, the alliance’s strength.

Adopt a plan for engagement with Ukraine. The JEF probably does not have an operational contribution to make to Ukraine’s self-defense through forward deployment. It could, however, become a primary platform for joint learning and exchange with the Ukrainian military. Ukrainian forces know more about how to confront today’s Russian military than anyone. JEF members could learn from Ukraine and could offer ideas (and potentially niche or specialized equipment and training) in the context of a joint exchange.

Develop the JEF’s coordination capacity. For nearly three years, the United States has led the Ukraine Defense Contact Group (UDCG), also known as the Ramstein group, which has been the primary coordination mechanism for fifty-seven countries in marshaling and organizing military support for Ukraine since the 2022 Russian invasion. U.S. leadership on Ukraine aid is increasingly uncertain, and although NATO is poised to integrate the coordination function for the time being, JEF members might usefully be prepared to step up in the event of roadblocks. In the longer term, the JEF could take lessons learned from the UDCG to be prepared to establish and lead similar coordination mechanisms in response to a future crisis.

Have a plan for Berlin and Warsaw. Germany and Poland are not JEF members, and they need not become JEF members. But Berlin and Warsaw are northeast Europe’s largest economic and military powers respectively, so the JEF should lay out a plan of engagement and coordination with them. This requires overcoming political jealousies in London and the region. A statement of intent by JEF members at the upcoming Tallinn meeting would be a good first step.

This moment demands not merely institutional upgrades of the architecture of European security, but a deeper cultural shift.

One of the reasons European leaders have failed to muster the political will and strategic vision to better confront today’s security threats and prepare for tomorrow’s is that European publics have not embraced the reality that their relatively comfortable way of life is under threat and will require substantial political and financial investment to protect.

Worse, many cannot imagine what indigenous European defense capabilities look like. They are so disconnected from a time when these were necessary at scale that the idea of a robust set of deployable capabilities spread across the continent seems a fantasy.

The countries of NATO’s northeast are leading the charge in adapting to the new reality. Building the effectiveness of an upgraded JEF would not only make a (modest) contribution to European security, but also would be a proof of concept—a demonstration that Europeans can make progress on the security challenges of this generation.