President Trump’s “America First” trade and foreign policy has pushed European and Asian allies to seek greater independence from the American arms industry and stepped-up cooperation with each other. This growing detachment risks undermining the dominance of the U.S. defense sector and weakening the country’s broader strategic objectives.
To preserve its position as the world’s leading arms producer, the United States must strengthen and sustain defense-industrial partnerships with foreign allies.
At July’s EU–Japan summit in Tokyo, leaders agreed to launch a new framework to accelerate defense-industrial cooperation. This initiative aims to institutionalize dialogue between the public and private sectors to strengthen supply chains and explore joint development of defense and dual-use technologies. It builds on years of incremental cooperation as Tokyo and Brussels have sought to deepen industrial ties amid rising geopolitical risks in their respective regions.
The Europe–Japan partnership in defense procurement gained prominence in 2022 when Japan announced the Global Combat Air Program, a sixth-generation fighter initiative with the UK and Italy. This marked a notable shift away from Japan’s traditional reliance on U.S.-made fighters. Key reasons behind this decision include the differences in procurement timelines and limited autonomy in U.S. development programs.
More recently, however, the move has taken on a political dimension. The Trump administration’s wavering commitment to the defense and economic ties with foreign allies, along with its threat to cut arms supply to Ukraine, reinforced concerns among officials from partnering countries about U.S. reliability as an arms supplier.
This has further accelerated European and Asian partnerships as a hedge against potential disruptions. Last November, Japan and the EU launched the “Japan-EU Security and Defence Partnership” and have since expanded cooperation in areas such as cybersecurity, satellite and quantum technologies.
Strategic consequences for the United States
The decoupling of allied defense industries from the United States poses three key risks to U.S. arms manufacturers and broader strategic interests.
First, it could undermine American innovation and industrial capacity. U.S. defense programs have long benefited from allied participation to sustain a technological edge and ensure cost competitiveness. For example, foreign partners played a vital role in the F-35 Joint Strike Fighter program, which would have been financially unfeasible without their early commitments.
Similarly, U.S.-Japan collaboration on the SM-3 Block IIA missile enhanced both countries’ missile defense capabilities. Mitsubishi’s third-stage motor and nose-cone technology contributed to the improved maneuverability and range. As allies grow independent from U.S. technology, opportunities for such beneficial collaboration may decline.
Second, reduced reliance on U.S. arms may erode American strategic influence. The U.S. has long leveraged its unique position as a leading supplier of advanced weapons to shape alliances and regional dynamics—from historically calibrating advanced fighter sales to Taiwan and Israel to suspending F-35 deliveries to Turkey over its purchase of Russian missile systems. If allies become self-sufficient or emerge as alternative suppliers of advanced weapons, the United States’ leverage through arms diplomacy could diminish.
Third, decoupling threatens interoperability. Modern warfare depends on integrated systems, and divergent arms supply chains make coordination harder. The war in Ukraine has exposed this challenge, with Ukrainian forces struggling to operate a patchwork of equipment from various donors. If allies continue to pursue independent procurement paths, future coalition operations will require costly efforts to standardize weapons and communications systems.
Reengaging allies to sustain defense leadership
A full reversal of this trend may neither be feasible nor desirable. Deeper EU–Japan collaboration would supplement strained American industrial capacity and enhance the collective capacity of Western democracies.
But the United States must avoid becoming isolated from these emerging industrial alliances. Defense policymakers should reframe allied industrial cooperation as a strategic asset—essential for maintaining the supremacy of the American arms industry and advancing broader U.S. strategic objectives—not as a liability or a concession.
This process begins with policy evaluations of proposed partnerships, led by the Department of Defense and supported by independent think tanks. These analyses can, for example, use rigorous metrics to identify and quantify areas where foreign partnerships would be most beneficial.
Meanwhile, Congress can play a key role in ensuring continuity. Legislative mechanisms—such as binding agreements or permanent funding authorizations—can shield international cooperation from executive branch fluctuations.
The implementation of the Australia-United Kingdom-United States (AUKUS) agreement offers a promising model. The 2024 National Defense Authorization Act includes four provisions to advance the goals of AUKUS, including authorizing the transfer of U.S. Virginia-class submarines to Australia, and streamlining export-control processes to accelerate cooperation on emerging defense technologies. Such efforts to codify frameworks signal a long-term U.S. commitment and reassure both allies and industry stakeholders.
To maintain its leadership in the defense-industrial sector, the U.S. must adapt to retain allied industrial partners. This means engaging more deeply, legislating more strategically and building partnerships that strengthen both industry competitiveness and national security objectives.