US hegemony weakens amid fragmentation of alliances

For eight decades, this strategic asset mattered more than pure military power because no U.S. rival could match it. With more than 50 treaty allies and formal security partners, the U.S. built the first truly global security system in history.

China has trading partners but only one security ally (North Korea), and Russia’s five allies are bound by dependence and coercion. Only the U.S. leads a worldwide coalition of countries that for generations have voluntarily chosen to bind their security to it.

To be sure, several presidents, most notably Donald Trump, have raised concerns about the costs of the alliance system. But what they see as a burden has repeatedly allowed the U.S. to mobilize coalitions when crises arise. In 1991, for example, the U.S. assembled a huge multinational force to drive Iraqi troops out of Kuwait. NATO allies, Arab partners, and Asian states provided troops, funding, and logistics.

Even during the much more divisive Iraq War in the 2000s, the U.S. was able to enlist partners. Four countries participated in the initial invasion, and nearly 40 deployed troops at some point in the war. Many contributions were small, and some consisted of a few hundred soldiers or specialized support units. But the political and military reality remained the same: even in contentious wars, U.S. power operated through coalitions rather than unilateral action.

The former unity is gone

The contrast with the current situation is striking. Amid rising tensions over Iran and soaring oil prices, the Trump administration has asked allies to help secure shipping through the Strait of Hormuz, one of the most important waterways in the global economy. Nearly a fifth of the world’s oil and liquefied natural gas shipments pass through this narrow strait connecting the Persian Gulf to international markets, making its openness directly important to allies.

Yet the response from U.S. security partners has been reserved, hesitant, or negative. Several major allies – including Spain, Italy and Germany – declined to participate. Australia said it would not send ships, and Canada ruled out offensive operations. France, Japan and South Korea have not committed warships to the U.S.-led mission. The UK says it is discussing options with partners but has not yet announced a deployment.

The trend is clear: Allies who once mobilized with the US now seem increasingly unwilling to bear the security risks under its leadership. In part, this hesitancy reflects the accumulated fallout over the years that Trump and his supporters in the MAGA movement have publicly disparaged allies, questioned security commitments, and viewed the alliance system as a burden rather than America’s most valuable strategic asset.

Disagreements within alliances are nothing new. NATO has survived divisive crises, from the 1956 Suez conflict to the Iraq War to the first Trump administration’s withdrawal from the Iran nuclear deal.

The security architecture is crumbling

But this time it’s not just about reluctant allies. A deeper shift is taking place. Key partners such as France and Italy have reportedly begun exploring the possibility of direct negotiations with Iran to ensure the safe passage of its merchant fleet through the Strait of Hormuz. While such talks are still tentative, the very fact that they are taking place is historic.

Energy markets help explain the urgency of the situation. Oil prices have jumped above $100 a barrel, and gas prices in Europe have skyrocketed due to the collapse of shipping. European governments fear that a prolonged closure of the strait could add to the economic hardship already weighing on their economies. But instead of coordinating a collective response through a system of alliances, several allies are exploring independent agreements with the very nation the U.S. has gone to war against.

For decades, U.S. leadership has discouraged precisely this behavior because of the understanding that separate deals with adversaries would undermine the cohesion necessary for alliances. Alliances are based on collective security, in which members face threats together. Once governments begin to negotiate their own exceptions with adversaries, the alliance ceases to function as a coordinated security network and becomes a loose amalgamation of national strategies.

Alliances rarely collapse suddenly. More often, they gradually erode as participants begin to secure themselves outside the system. If European states manage to negotiate separate assurances with Iran instead of working through the alliance system, the consequences will extend far beyond the Persian Gulf. Such an outcome would strike at the very heart of American power and could mark the beginning of a broader breakdown of the global security architecture with the United States at its center.

That architecture has taken generations to build. Fragmentation of the security system could destroy it much more quickly. And make no mistake: if the U.S. loses the system of alliances that reinforces its power, it will face not just a less hospitable world, but an unfamiliar world that will no longer be shaped by the hegemonic power that most Americans alive today have always taken for granted.