How Allies Could Help Preserve U.S. Military Reach

The strategy gives priority to homeland defense and the Western Hemisphere, while making deterrence of China in the Indo-Pacific central. At the same time, it describes alliances as a “defensive perimeter around Eurasia” and calls for “critical but more limited” American support. That combination suggests a more selective U.S. military presence without abandoning a wider strategic position.

If regional forces can hold the line during the opening phase of a crisis, Washington may gain time to judge where intervention is needed and avoid committing forces to several theaters at once. It could also vary its permanent presence without every reduction amounting to a withdrawal. But the arrangement depends on whether allies can sustain their own defenses—and on how much they still rely on American intelligence, transport, communications, maintenance and supplies.

Europe illustrates both the promise and the constraint. NATO Secretary General Mark Rutte has said the United States must prepare for more than one theater and that European and Canadian allies need to carry more of their own defense burden. Stronger European forces could hold territory and keep reinforcement routes open. Yet air defense, intelligence, surveillance and reconnaissance (ISR), strategic lift, and command-and-control capabilities remain unevenly distributed across the alliance. A prolonged operation could still depend on American support.

At the Warsaw Security Forum on 12 October, NATO’s Supreme Allied Commander Europe, General Alexus Grynkewich, described a “theory of victory” built around “block, blunt, and break”: deny a rapid seizure of allied territory, stop an offensive from gaining momentum, then dismantle the military system sustaining it. The sequence depends on local defenses preventing an early collapse and creating time for additional forces to arrive. Allies, however, must absorb more of the initial pressure, and their willingness to do so partly rests on whether they trust that U.S. support will come when needed.

The interval could be shorter in the Indo-Pacific. Japan and Australia can offer maritime, air, logistical and intelligence support; the Philippines provides U.S. forces access to additional operating sites. South Korea is expected to take primary responsibility for deterring North Korea, with more limited U.S. support. Taiwan presents a harder test: at a March Senate Armed Services Committee hearing, Chairman Roger Wicker noted that the unclassified National Defense Strategy does not mention Taiwan, although the National Security Strategy identifies it directly. A rapid attack could alter the military balance before Washington decides how to respond.

That vulnerability gives an adversary an incentive to move quickly and create a fait accompli, forcing the United States to commit scarce forces earlier than planned. In the Gulf, meanwhile, the immediate task may be keeping bases and access routes usable amid repeated air and missile attacks. Across theaters, mobile U.S. forces can reinforce only if a viable position remains by the time they arrive.

The strategy does not say Washington intends to intervene more often. But regional defenses could make limited operations more feasible: U.S. forces might halt an offensive or restore a position, then withdraw as allies sustain the result. That exit is not guaranteed. If local forces cannot hold the gains, Washington may have to stay or accept their erosion. The authors Mearsheimer and Walt, writing about offshore balancing, argue that local powers should prevent regional domination, with direct U.S. intervention when they cannot. The strategy appears to retain a broader set of U.S. concerns, including military access, allied security and shifts in regional power.

Ultimately, redistributing defense responsibilities may preserve American reach while reducing standing commitments. But the same U.S. intelligence, communications and logistical systems that support allies may be needed across several theaters—and could be targeted or disrupted. If allies cannot operate without them, the burden has shifted on paper more than in practice, leaving the simultaneity problem and the risk of overstretch intact.