The Op-ed by EPP Secretary General Antonio López-Istúriz, published on "El Mundo", focusing on the Nato Summit. In the run-up to a NATO summit, in which Allies are likely to debate the future of the alliance, an air of optimism currently surrounds the transatlantic partnership. We have a trio of summits in June, including the G7 on the 11^th, the NATO summit on the 14^th and the EU-US summit on the 15^th. After years of inaction, long-standing issues are again being addressed: climate diplomacy, trade disputes, digital taxes, and democratic backsliding throughout the world. Moreover, the new US administration has shown its willingness to engage in good faith with its partners and drive a common agenda.European defence initiatives will arguably test this air of optimism. The idea of the EU as an active player, with its own defence and military capacities, has always ruffled some feathers: in some European capitals and especially in Washington. Here again, however, I believe the tide may be shifting. After years in which Europe felt alone in the world, European initiatives aiming to integrate national armed forces, such as the Permanent Structured Cooperation (PESCO), or to coordinate national investment in defence, such as the European Defence Fund (EDF), have come to be seen not just as a luxury but a necessity. The Center for American Progress, a think tank close to the administration, illustrated this shift with its recent paper arguing that the US should actively support Europe’s ambitions on defence. Indeed, consensus seems to be emerging that the EU is not an obstacle in the way of NATO or of the United States’ core defence interests. In fact, the EU can be a complementary actor, which helps to avoid redundancies and duplication. The United States’ participation in PESCO’s project on military mobility is yet further proof.As a transatlanticist, I believe the EU needs to push forward and take on more responsibility, always keeping it mind NATO’s fundamental role in the transatlantic defence architecture. EU-NATO cooperation is not a topic embraced only by some policy wonks in certain far-off corners of Brussels. Even the Secretary General of NATO himself has loudly and publicly spoken about the need for this cooperation.In a report of the European Parliament´s Foreign Affairs Committee, we have rightly stressed that the transatlantic community can only successfully tackle security challenges by further enhancing cooperation and by taking the EU-NATO partnership to a new level. Cooperation between the EU and NATO is of course already happening — and it is working. Both the EU and NATO are already coordinating activities on military mobility, defence against cyberattacks and operations in the Western Balkans, for example. Just in the last decade, the EU and NATO went from having no regular channels of communication to enjoying a real organisation-to-organisation, intentional and dynamic relationship.EU Member States and NATO allies face a common reality of systemic competition, along with numerous new and common threats, that have a significant impact on the security of our citizens. Our rivals and authoritarian opponents are not just using military force, but a wide range of tools aimed at weakening our democracies. We have only too recently understood how powerful these tools can be: hybrid threats, cyber-attacks, foreign interference, tampering of elections and disinformation campaigns.   Though the EU and NATO are not the same, their competences and expertise can be complementary in addressing these challenges. Addressing Russian aggression, for example, requires traditional deterrence resources held by NATO, as well as alternative tools like economic sanctions or mechanisms to counter disinformation or electoral interference, all of which the EU possesses. The difference is understandable and evident in how the EU and NATO each perceive and rank threats. After all, the EU is a political union with a small military arm deployed only for very specific missions and tasks, while NATO is a military and political alliance in charge of galvanising’ the collective territorial defence of its members. While the EU sees China, as both an economic competitor, systemic rival and cooperation partner, NATO’s remit understandably has little appetite for the latter. The EU-NATO relationship now presents a unique opportunity for closer collaboration. Member States are currently constructing an “EU Strategic Compass” for security and defence: the culmination of a two-year process to identify areas where the EU can develop its own defence mechanisms, based on a common threat analysis by Member States. At the same time, NATO is expected to update its “Strategic Concept“ outlining the alliance´s vision of its security environment and its broader goals for the coming decade. These two assessments will provide a clear window of opportunity for setting coherent priorities and identifying additional synergies. The European Union and NATO have different mandates; but each can and should complement the other. We have to strike the right balance between ambition and realism. The EU will not build a strategic culture over the course of half a decade. But it can, and is, making serious steps by addressing the fragmentation of European defence industries, investing in interoperability, conducting common threat analyses, and expanding military and civilian missions and operations. For too long, we sat on the bench while our adversaries coordinated their activities with one another. It is high time we move past divisions holding us back and get serious about our own defence. The best way to do so is by investing in the current institutions we have: the EU and NATO. Those opposing this cooperation, and opposing further EU efforts to strengthen its defence capacity, are only playing Russia and China’s game: to keep Europe weak and divided.In an era of great-power competition, we need the EU to become a stronger actor and partner, including in vital areas of security and defence. Strengthening the strategic partnership between the European Union and NATO is necessary to achieve this goal and meet our common security challenges. Antonio López-Istúriz White Secretary General of the European People´s Party Member of the European Parliament and Rapporteur of the Report on “EU-NATO cooperation in the context of transatlantic relations”