The Atlantic Brief: After the U.S. Midterms, Trans-Atlantic Defense Cooperation

The webinar was the third joint event in The Atlantic Brief series, organized by the Royal United Services Institute and War on the Rocks. It focused on the future of trans-Atlantic defense cooperation after the U.S. midterm elections. That matters because the discussion connected American policy choices with European defense responsibilities, NATO, and Ukraine.

Rachel Ellehuus, RUSI’s Director-General, joined Kori Schake, a senior fellow at the American Enterprise Institute and contributing editor to War on the Rocks. Michael Hardwood, a former British defense official and Royal Air Force fast-jet pilot, also participated. Their experience covered armed forces, diplomacy, and foreign policy.

Andrew Gee, RUSI’s Director of International Security, moderated the event. Nicole Wiley, War on the Rocks’ Membership Editor, served as co-moderator. The panel also examined European defense investment, strained supply chains, and responses to Russian hybrid pressure.

Trans-Atlantic defense cooperation means North American and European countries working together to deter threats and protect their shared security. In this article’s setting, it links experts and policymakers from the United States, the United Kingdom, and continental Europe. The concept matters because no single partner handles every military, political, or industrial challenge alone.

Cooperation can involve common planning, military deployments, intelligence sharing, weapons production, exercises, diplomacy, and support for partners such as Ukraine. NATO is the main military framework, while European states can also coordinate through the European Union. The key mechanism is alignment: governments decide priorities, share burdens, and make their capabilities usable together.

The webinar examined this cooperation after U.S. midterm elections. It connected American force posture with NATO relations, European defense investment, supply chains, and responses to Russian hybrid pressure. These issues show that the relationship involves both battlefield capabilities and political decisions.

U.S. midterm elections are nationwide elections held midway through a presidential term. Voters choose members of the House of Representatives and usually a portion of the Senate, along with many state and local officials. The article does not give election results; it presents the webinar as a discussion of what the elections could mean.

The mechanism is political control. Congressional majorities influence defense budgets, military authorities, oversight, sanctions, and aid legislation. A changed balance can therefore affect the resources available for U.S. force posture, the administration’s room to maneuver, and the durability of support for Ukraine. It can also alter how Washington debates NATO commitments.

Those effects are not automatic. The president still leads foreign policy, while Congress controls major funding and oversight decisions. The webinar planned to connect the midterms with NATO, U.S. force posture, and Ukraine support, alongside European investment and responses to Russian pressure.

NATO is a 32-member alliance as of 2026. Its scale comes from combining North American and European populations, economies, armed forces, bases, and defense industries. The supplied article does not state NATO’s membership or resource totals, so these figures use established current background knowledge. The alliance’s size gives it broad military and economic depth.

Members contribute in different ways. They provide soldiers, ships, aircraft, air defenses, cyber capabilities, logistics, intelligence, and command structures. They also fund national defense and common NATO activities. Larger economies generally bring greater financial and industrial capacity, while smaller members may provide specialized forces, strategic locations, or niche capabilities.

The value of these contributions depends on readiness and coordination, not only totals. Forces must train together, communicate, move across borders, and receive compatible equipment and supplies. That is why the webinar’s focus on European investment and strained supply chains matters to the alliance’s practical strength.

U.S. force posture means the location, size, readiness, and missions of American military forces. Support for Ukraine includes military assistance, funding, training, and political backing. If Washington reduces its presence or support, European allies may need to cover more surveillance, air defense, logistics, ammunition, and deterrence tasks. The article frames these as central post-midterm questions.

The mechanism is shared burden. U.S. capabilities often provide scale, high-end technology, transport, intelligence, and command support. European allies can respond by increasing defense spending, expanding production, strengthening national forces, and coordinating deployments. They may also need to sustain Ukraine more directly if American assistance becomes less certain.

The outcome depends on political choices after the elections. The webinar did not announce a policy decision. Instead, it brought together experts to assess implications for NATO, Ukraine, and European defense investment as trans-Atlantic politics shift.

European defense investment matters because NATO readiness requires available, trained, and properly equipped forces. Spending supports personnel, weapons, maintenance, infrastructure, exercises, and research. The article highlights European investment as a major issue because stronger European capabilities can reinforce trans-Atlantic defense cooperation and reduce pressure on limited national resources.

Reliable supply chains are the practical mechanism behind readiness. Military units need steady access to ammunition, fuel, spare parts, electronics, and replacement equipment. If production is slow or concentrated in vulnerable links, an extended crisis can exhaust stocks or delay reinforcement. Strained supply chains therefore affect both national forces and collective NATO plans.

The webinar paired these concerns because money alone does not guarantee usable power. European governments must turn investment into interoperable capabilities and resilient production. The article does not provide spending totals or specific shortages, but it identifies supply-chain strain as a key future defense question.

NATO’s collective-defense system is built around the principle that an attack on one member concerns the entire alliance. In practice, members consult, assess the threat, and decide what assistance is needed. That assistance can include military forces, intelligence, air defense, cyber support, sanctions, or other measures. The purpose is deterrence: an aggressor should expect a wider response.

Russian hybrid pressure is difficult because it can blend disinformation, cyberattacks, sabotage, political influence, coercion, and economic pressure. Actions may remain below the level of an obvious armed attack. Attribution can take time, and allies may disagree about the evidence or the appropriate response. NATO must coordinate defense, while the EU may have stronger tools in areas such as regulation, finance, and sanctions.

The article presents leadership between NATO and the European Union as an open question. Its panel was set to examine how shifting European politics could affect that division of responsibilities and the wider trans-Atlantic response.