Recently, the Trump administration reportedly told its allies it would stop participating in military exercises in Europe, including those already scheduled for 2025.
I served as deputy assistant secretary of Defense for Force Education and Training in the Biden administration, where I had policy oversight of military exercises. I can say with confidence that the decision to pull out of European exercises is a severe strategic mistake. There are three reasons why.
First, exercises with allies are the mortar in the foundation of U.S. defense strategy: they keep the whole thing together. This is because the United States military doesn’t fight alone. It never has, and, barring a tectonic shift in U.S. strategic and operational concepts, likely never will. Therefore, anything that erodes the ability of the United States and its allies to fight together threatens the viability of U.S. military power.
Exercises are the best mechanism available to forge interoperability and validate that U.S. and allied forces are ready for the fight. Readiness is about more than weaponry — it’s the cognitive interoperability of the personnel using the weapons that makes the difference. Only repeated engagements synthesizing the smallest tactical challenges (like how to make two different radios talk to each other) with the biggest strategic goals (how to ensure multiple armies can secure territory and deter an adversary) can create the kind of lethal combat readiness Americans expect and the world envies.
Second, the only currency that buys that interoperability is time, which the logistical chaos created by pulling out of exercises wastes needlessly. Because of their complexity, even simple exercises can take at least a year to plan. Steadfast Defender 24, the largest NATO exercise since the end of the Cold War, took years to put together. It engaged 90,000 forces from 32 countries and involved 80 air platforms, 50 ships and 1,100 combat vehicles.
Its purpose was nothing less than the demonstration of NATO’s capability to conduct multi-domain operations, at scale and at range, over a sustained timeline — essentially, proving NATO could once again make good on its charter’s collective defense clause, Article 5. For something this complex, one nation canceling or altering an exercise can undermine the entire plan.
Third, trust is won in drops but spilled in buckets, and a public display of American unreliability spills gallons of trust between the U.S. and its NATO allies upon whom it has relied mightily. Recall that the only time NATO has invoked Article 5 was in response to the 9/11 attacks on the United States, which it did within 24 hours. Within the following month, NATO launched its first-ever anti-terrorism operation, Eagle Assist, which saw 830 airmen from 13 NATO countries fly 360 sorties. That kind of rapid, almost reflexive, response is the product of the trust generated by decades of training, exercising, learning and sweating together, side by side.
The United States, no matter the foreign policy bent of its leadership, cannot afford to go it alone. And by any metric — be it the global resurgence of far-right nationalism, the decrease in freedom at the ballot box, or the accelerating effects of climate change that can spark or entrench conflict — the trend does not look positive for global stability. In a world such as this, the United States needs its friends. Friends that will show up.
In 2023, Congress passed a bill — co-sponsored by now-Secretary of State Marco Rubio — that requires congressional approval before any president withdraws from NATO. Putting aside whatever the intent had been behind the Trump administration’s exercises announcement, the impact is the very same unilateral withdrawal the bill tried to prevent.
The purpose of NATO is the collective defense of its members. Refusing to participate in the exercises that generate the readiness and capacity to provide that collective defense is tantamount to refusing to be a party to NATO.
Already, the Trump administration’s signals to Europe have created fear that they will suddenly need to provide for their own defense: Poland has publicly pondered acquiring nuclear weapons, Germany is looking to strengthen Europe’s nuclear deterrent capability, and France has suggested extending its own nuclear umbrella. Combine the remilitarization of the European continent during a hot war between Russia and Ukraine with surging right-wing nationalism, and you get the obverse of “a Europe whole and free.”
Military exercises between U.S. and allied forces aren’t sentimental time-wasters. They are a downpayment on the continuation of the American way of warfare. Whether, where, and how the U.S. fights is a worthwhile debate — but strategy drives operations, not the other way around. Suddenly pulling out of military exercises forces strategic change through kneecapping current U.S. operational capability. This is not the behavior of a great power. Unless and until the United States decides to recall its forces and retreat behind its borders, military exercises will matter.
Caroline Baxter served as deputy assistant secretary of Defense for Force Education in Training during the Biden administration.
