For more than three decades, the United States carried the largest share of NATO's military burden while many European allies spent far less on defense than Washington wanted. The imbalance survived the Cold War, multiple U.S. administrations and repeated debates over burden sharing. Only in recent years — following Russia's 2022 invasion of Ukraine and renewed pressure from President Donald Trump — have many NATO members begun significantly increasing defense spending.
Defense analysts say the answer to why this gap persisted for so long lies in a combination of post-Cold War optimism, domestic political priorities and an American defense umbrella that convinced much of Europe it could safely spend less on defense without sacrificing its security. The collapse of the Soviet Union reinforced that mindset across European governments, which moved to collect a so-called "peace dividend" by redirecting resources toward domestic priorities.
What the Right Is Saying
Conservative critics argue that American taxpayers effectively subsidized Europe's security for decades, allowing allies to redirect resources away from defense. In a 2011 farewell speech in Brussels, then-War Secretary Robert Gates warned of a "dim if not dismal future" for NATO if European governments continued underinvesting in their militaries, cautioning there would be "dwindling appetite and patience" among American lawmakers and taxpayers to bear a disproportionate share of the alliance's defense costs.
Former Deputy Assistant Secretary of Defense for Europe and NATO Jim Townsend told Fox News Digital that "every administration has been pushing allies to spend more money on their own defense." Critics from the right describe this dynamic as a "moral hazard" problem: because the U.S. commitment to NATO was viewed as ironclad, allies could spend less on their own militaries without facing full consequences.
What the Left Is Saying
Progressive critics of NATO's spending structure argue that the alliance's burden-sharing arrangements reflected deliberate American foreign policy choices rather than European free-riding. Barry Posen, a professor of political science at the Massachusetts Institute of Technology, told Fox News Digital that "for much of the post–Cold War period, it is fair to say that Europeans underinvested in defense, partly because threats were low, and partly because a series of U.S. presidents did everything they could to convince Europeans that we would stay there forever."
Left-leaning foreign policy analysts note that European nations invested heavily in social welfare programs during this period — expanding healthcare systems, pensions and higher education — which became deeply embedded in domestic politics. They argue this reflected democratic choices by European voters prioritizing different values rather than simple unwillingness to contribute to collective defense.
What the Numbers Show
The scale of European underinvestment is documented in historical spending data. Between 1992 and 1999, defense spending among European NATO members fell 22%, establishing a pattern that persisted for decades even as the United States maintained troops in Europe and continued serving as NATO's ultimate security backstop.
NATO established its benchmark for members to spend at least 2% of GDP on defense after Russia's annexation of Crimea in 2014. While spending gradually increased following that threshold, progress remained uneven across the alliance. The issue dates back further than recent decades: in 1953, President Dwight D. Eisenhower warned European allies that "the American well can run dry" and pressed them to assume a larger share of the defense burden.
As European militaries shrank over decades, many allies grew increasingly dependent on American capabilities including logistics, intelligence, missile defense, strategic airlift and nuclear deterrence. NATO Secretary-General Mark Rutte said earlier in 2026 that "we are still having a strong, conventional U.S. presence in Europe, and, of course, the nuclear umbrella as our ultimate guarantor."
The Bottom Line
The decades-long defense spending gap between the United States and European allies reflects structural incentives that proved difficult to change: American security commitments reduced pressure on allies to spend more, while domestic political priorities in Europe made military cuts politically easier than reductions to popular social programs. Only Russia's 2022 invasion of Ukraine and sustained pressure from the Trump administration appear to have fundamentally shifted the calculus for many NATO members. The question now is whether this increased spending represents a lasting change or another temporary adjustment in a pattern that has persisted since NATO's founding.
What to watch: Whether European defense spending increases prove durable once immediate security concerns moderate, and how future U.S. administrations handle burden-sharing discussions with allies who may face their own domestic political constraints on military investment.