For decades, Europe’s defense posture has remained heavily dependent on the United States, a reliance that has drawn renewed scrutiny amid shifting global security dynamics. Despite repeated calls for increased defense spending across the continent, many European nations continue to invest well below levels matched by the United States, raising concerns over the sustainability of Western security arrangements.

Since 2010, European NATO members have significantly underfunded their militaries relative to the United States, with the total shortfall in defense spending estimated to approach $8 trillion when adjusted to 2025 dollars. This figure reflects a longstanding imbalance in burdensharing, as U.S. defense budgets have consistently outpaced those of their European allies even as threats from Russia and China have markedly intensified. Between 2010 and 2025, Russia and China increased their military expenditures substantially in real terms, underscoring the urgency facing Western security institutions.

European governments have repeatedly pledged incremental increases in defense budgets, aiming for targets such as 2 percent or 3 percent of GDP by 2030 or 2035. However, analysts argue these commitments fall short of compensating for decades of comparatively low investment. Moreover, some calculations inflate apparent defense spending by including accounting measures such as military pensions, obscuring the true extent of underspending. Critics contend that raising budgets by modest amounts will not quickly rebuild eroded capabilities in nuclear, conventional, and technological domains.

The uneven defense investment in Europe has broader implications beyond military readiness. Many European welfare states depend on the security umbrella provided by the United States; Sweden, for example, maintained an average defense spending of roughly 1.1 percent of GDP between 2010 and 2020, despite only formally joining NATO in 2024. Advocates of Europe’s social and economic model caution that generous welfare systems depend on continued economic growth and stable security environments, conditions currently underpinned by American military power.

Economic considerations further complicate the picture. Europe’s economic model is heavily reliant on global free trade, which depends on a stable international order sustained by naval power and the protection of shipping lanes. The U.S. Navy has historically fulfilled this role, bearing the cost of securing maritime trade routes vital to European economies. Without this hard power, critics warn, the foundations of Europe’s prosperity and social support programs could be undermined.

There is ongoing debate about the future of transatlantic security and Europe’s capacity to assume greater responsibility for its own defense. Some observers attribute the current situation to a failure of European political leadership to confront difficult truths about security and spending priorities. Others highlight the need for structural reforms in European economies to promote growth and innovation, factors essential for sustainable defense investments.

As geopolitical competition intensifies and the United States signals shifts in its foreign policy focus, European nations face mounting pressure to reassess their defense strategies and economic models. While many Europeans acknowledge the need for increased defense spending, public and political willingness to accept the necessary sacrifices remains uncertain. The coming years are likely to test the resilience of the transatlantic alliance and Europe’s ability to adapt to an evolving security environment.