Taiwan has proposed an 18% increase in its defense budget for 2027, pushing military spending above 3% of GDP as Chinese military and political pressure grows. The move comes as the United States remains engaged in its six-month war with Iran and has deployed its last aircraft carrier in the western Pacific to the Middle East, temporarily leaving the region without a US carrier presence.
Taiwan’s move captures a broader shift underway among America’s allies. For decades, Washington has urged its partners to invest more in their own defense. Many are now doing so, but for reasons that go beyond burden-sharing. They are also preparing for a world in which US priorities, commitments and crisis decisions can shift more quickly than allies can influence.
The Changing Logic of Alliances
What Washington views as overdue burden-sharing, many partners regard as prudent hedging. Burden-sharing reflects confidence in an alliance; hedging reflects efforts to preserve flexibility when reliance on that alliance feels uncertain. America’s allies are pursuing both simultaneously.
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Across Europe, the Middle East, and Asia, partners are strengthening military capabilities, broadening relationships, and expanding strategic options. These efforts reflect Washington’s longstanding call for greater responsibility while also revealing doubts about dependence on American power when allies have limited influence over US decisions.
The underlying issue is credibility, which rests on confidence that US objectives are clear, consultations are meaningful, and policy remains consistent enough for allies to plan. As that confidence weakens, allies create additional options, reduce exposure, and prepare for a wider range of contingencies.
These adaptations strengthen national resilience but may also reshape alliance dynamics, complicating crisis coordination and reducing some of the advantages the United States derives from its alliance network.
America’s alliances remain a strategic asset, extending US influence beyond what Washington could achieve alone. Preserving that advantage requires more than greater allied defense spending; it requires sustaining the confidence that makes cooperation possible.
The Middle East: Protection and Exposure
The Gulf states illustrate the most complex form of alliance adjustment. They continue to view American military power, intelligence cooperation, arms relationships, and diplomacy as central to their security. But they also recognize that close reliance on Washington can expose them to risks over which they exercise little influence, particularly when US confrontations with regional adversaries escalate.
The 2019 attacks on Saudi Arabia’s oil facilities marked an important moment in this evolution. Despite extensive US-Saudi security cooperation and a substantial American military presence in the Gulf, the attacks raised questions about Washington’s ability and willingness to respond decisively to asymmetric threats.
The US withdrawal from Afghanistan offered a related lesson. It demonstrated how rapidly political decisions in Washington could reshape America’s regional engagement and highlighted the limited influence partners possess over those decisions.
The ongoing conflict with Iran has brought these concerns into sharper focus. Gulf governments share Washington’s interest in containing Iran while remaining directly exposed to retaliation against regional targets, disruptions to maritime commerce, and risks to global energy markets.
Beyond the conflict itself, Washington’s objectives have appeared unsettled, shifting between diplomacy, coercive pressure, military action, and renewed negotiations without a clearly defined end state. Divergent messages from President Donald Trump and senior officials, along with limited consultation, reinforced perceptions of US policy unpredictability, leaving allies to adjust to decisions they did not shape.
This dynamic predates any single administration. Since returning to office, however, President Trump has intensified these concerns through a more transactional approach to alliances, shifting objectives, inconsistent messaging, and questions about the durability of long-standing commitments.
Gulf governments therefore continue to seek American security guarantees because no other external power offers comparable military capabilities. At the same time, they have expanded relationships with China, Russia, and other partners to increase strategic flexibility and reduce dependence on any single actor.
Europe: Capability as Insurance
Europe reflects the same broader trend through a different set of concerns. European governments are less focused on being drawn into US conflicts than on the long-term consistency of American commitments.
Russia’s invasion of Ukraine accelerated increases in defense spending, weapons production, air defenses, ammunition stockpiles, and defense industrial cooperation. These initiatives respond to longstanding American calls for greater European responsibility, but they also reflect misgivings about the reliability of US support and the need for greater European capacity should American policy priorities change. Those concerns have deepened amid uncertainty over continued support for Ukraine and President Donald Trump’s repeated questioning of NATO commitments, intensifying debate over the future of American security guarantees.
European defense investments therefore represent both burden-sharing and strategic insurance. A stronger European pillar strengthens NATO while providing greater resilience should future US support become delayed, limited, or more conditional. Over time, however, these capabilities could also provide European governments with greater latitude to pursue policies that diverge from Washington’s preferences.
Asia: Resilience Within Dependence
Asia’s allies face a different strategic environment but a similar calculation. Japan, South Korea, Australia, and the Philippines continue to rely on the United States as the indispensable guarantor of regional security while investing more heavily in their own resilience.
Japan’s historic expansion of defense spending, Australia’s deeper defense cooperation through AUKUS, and South Korea’s continuing debate over an independent nuclear capability all reflect efforts to strengthen national capabilities while preserving reliance on the alliance with Washington. The goal is greater strategic flexibility within an alliance that remains essential but whose future direction appears less certain.
The Philippines highlights the continuing importance of American credibility. As confidence in US engagement has grown alongside concern over China’s maritime activities, Manila has deepened defense cooperation, granted greater access to US forces, and strengthened operational coordination with Washington. Allied behavior reflects judgments about the credibility and reliability of American commitments. Whereas confidence encourages deeper cooperation, uncertainty encourages greater hedging.
The Strategic Consequences of Alliance Adaptation
The central question for Washington is not why allies are becoming more capable, but why so many now view greater national resilience as essential. Stronger partners can reinforce the American-led alliance system, but they also reflect preparation for uncertainty in US policy and crisis decision-making.
The Gulf experience illustrates this dilemma. States that depend on American security guarantees also recognize that they may bear the consequences of decisions made in Washington over which they have limited influence. The Iran conflict has reinforced concerns about US objectives, consultation, and crisis management.
Washington has long encouraged allies to assume greater responsibility for their own security. It is succeeding — but with an unintended consequence. Many allies are strengthening themselves not only because the United States asked them to, but also because confidence in the predictability and durability of American policy has weakened.
This trend predates any single administration, though President Trump has amplified it through a more transactional approach to alliances, shifting objectives during crises, inconsistent messaging, and questions about the durability of long-standing commitments.
For the United States, the challenge extends beyond any single alliance or region. Credibility remains one of America’s greatest strategic assets, enabling coordination, risk-sharing, and collective action. As confidence weakens, alliances become more transactional, and strategic flexibility increasingly takes precedence over strategic alignment.
Greater allied capability can strengthen the US-led alliance system, but only if allies remain confident in American leadership. Washington wanted partners that could shoulder more responsibility; it should also want partners confident enough to do so alongside the United States rather than preparing to act without it.
