It’s Time to Recognize Sustainment as a Strategic Imperative

Army Artillery Firing

Editor’s note: This is the second installment of a two-part series on the contemporary challenges to offensive maneuver based on observations from the war in Ukraine, and the implications for the U.S. Army. 

In a previous article, “Ukraine and the Future of Offensive Maneuver,” Stephen Biddle rejected recent claims that an era of defensive dominance had dawned. As he noted, offensive maneuver has long been difficult against prepared defenses arrayed in depth. That is still the case. Moreover, Ukraine’s successful counter-offensives in the Kharkiv and Kherson regions — though not without their missteps and heavy costs, especially as regards the latter — should demolish the argument that offensive maneuver is dead. It can still succeed with proper preparations and force employment, though it might proceed incrementally and painfully against a competent foe. To advocate a significant redesign of U.S. ground forces at this stage, therefore, would be premature. Things can change, of course. But thus far, events in Ukraine suggest the U.S. Army’s Six Modernization Priorities are largely on track (though Army leaders should consider giving more attention to logistical capabilities). Modern militaries, like their predecessors, are best served by maintaining a flexible balance between offensive and defensive capabilities rather than going all in on one or the other. 

That said, there are several issues the U.S. Army should address regarding the sustainment of large-scale combat operations, whether offensive or defensive. To do this, sustainment should be elevated to a principle of war to underscore the strategic importance of logistics and to provide an imperative for the better integration of America’s defense industrial base into U.S. deterrence and defense strategies. Some of these issues the Army can address with modifications to its new operations manual, Field Manual 3-0 (2022), and its logistics manual, Field Manual 4-0 (2019). Specifically, Field Manual 3-0 should afford at least as much importance to contested logistics as it does to contested deployments and offer operational planners some hypothetical scenarios or historical examples of planning under a range of logistical constraints. Field Manual 4-0 should explicitly elevate sustainment to a principle of war and thereby require Field Manual 3-0 to follow suit.  

The Ammunition Crisis

Although offensive maneuver is not dead, the U.S. Army does have some work to do with respect to the way it thinks about large-scale combat operations. In fact, even if offensive maneuver were not possible and the war in Ukraine became one of attrition resembling the trench warfare of World War I, large-scale combat operations would still take place. They would not necessarily involve major breakthroughs and the recapture of large sections of Ukrainian real estate, but they would still likely require significant ammunition expenditure as well as the possible heavy consumption of other war material. For that reason, the Army would do well to examine more closely what some analysts are referring to as a “crisis over artillery ammunition.” 



The Ukrainian Armed Forces have reportedly consumed an average of 100,000 rounds of 155mm artillery ammunition per month. However, the U.S. defense industry can replace only 14,000 rounds per month, though that number should increase to 20,000 rounds per month over the next two years. The story is similar for Stingers, Javelins, high mobility artillery rocket systems (HIMARS), and other critical weapons. Simply put, the rate of material consumption in this war, especially as regards artillery ammunition, is outpacing the rate of resupply. This crisis is the result of three factors: a production capacity established in prewar conditions, the need to honor the broad range of U.S. strategic commitments, and Ukraine’s unanticipated rate of material consumption.

Admittedly, the U.S. government is swiftly generating new contracts to enable industry leaders to close the gaps between production and consumption. But the defense industry may need months (or years in some cases) to bring production up to scale. Meanwhile, the center of gravity for the Ukrainians is material support from the West. Without it, the Ukrainian Armed Forces, brave and skillful as they are, cannot sustain the type of large-scale combat operations necessary to retake the territories they lost to Russian aggression. 

The crisis has received only limited attention so far because Russian stockpiles of war material, including artillery ammunition, also seem to be running low. Both sides will likely have to reduce their tempo of operations and adjust the scope of their operations as a result. For the Ukrainians, however, such adjustments represent a lost opportunity. A drop in the rate of resupply means a loss of valuable operational momentum and allows the Russians time to rearm and refit. At the same time, Russian long-range missile and artillery strikes against Ukrainian civilians and critical infrastructure continue, thereby adding criminally to the noncombatant death toll.

Getting Serious about Sustainment

Clearly, some of the root causes of this logistics crisis fall outside the Army’s purview. But there is still a great deal it can do. 

First, the Army should revise the tone of its new operations manual, Field Manual 3-0, which reorients Army thinking toward major wars after decades of fighting smaller conflicts. That was an important shift. But Field Manual 3-0 also assumes the logistical support the Army needs to fight large-scale combat operations will be there. As the budding ammunition crisis has shown, this is not a safe assumption. This conflict has not tested U.S. capacity to transport material across the Atlantic Ocean and through Central and Eastern Europe under fire, though the Russians have the capability to interdict logistical flow throughout the length of these supply lines. Another adversary, such as the People’s Republic of China, might choose to attack U.S. supply lines. As research from the U.S. Army’s Strategic Studies Institute shows, China and Russia have already penetrated U.S. supply chains with disruptive cyberattacks. Hence, we cannot assume the deployment of war material from the United States to the European or Pacific theaters will be uncontested in a future conflict. 



Second, the U.S. Army should revise its logistics manual, Field Manual 4-0. The manual is a commendably realistic and painstakingly detailed document that explicitly recognizes the challenges of fighting in the modern battlespace. Indeed, the Army’s Field Manual 3-0 would benefit from a similar dose of realism. But Field Manual 4-0, too, needs to up its game. As explained in its sister document, Army Defense Publication 4-0 (2019), logistics falls under sustainment, which is “accomplished through the coordination, integration, and synchronization of resources from the strategic level through the tactical level in conjunction with our joint and multinational partners.” Yet unlike in partner forces such as the British Army, Field Manual 4-0 and Army Doctrine Publication 4-0 classify sustainment as a warfighting function rather than as a principle of war. A warfighting function is merely a “group of tasks and systems united by a common purpose that commanders use to accomplish missions and training objectives.” In other words, the U.S. Army is not on the same page as the British Army, one of its most consistent allies, in terms of the importance it attributes to sustainment (or what the British call sustainability). Ironically, the Russian army, as heir to the Soviet system, also sees logistics as a principle of war. 

The U.S. joint force typically forms the hub of military interventions involving alliance or coalition partners, so it has the responsibility of synchronizing the efforts of those partners by strengthening their networks. In cases of a disconnect over the value accorded to something as crucial as logistics, the U.S. Army — as the logistics integrator of the joint force and its multinational partners — should round up rather than down. Elevating sustainment to a principle of war solves that problem and acknowledges sustainment’s role as an indispensable guideline for strategic planning. 

To be sure, the U.S. military has had a love-hate relationship with the principles of war. Even the U.S. Army’s definition of a principle, a “comprehensive and fundamental rule or an assumption of central importance that guides how an organization or function approaches and thinks about the conduct of operations,” is unnecessarily cumbersome. It does, however, convey the right sense. Sustainment, stripped of its doctrinal verbiage, can be thought of as production capacity combined with the rate of flow, or delivery, into the theater of war. It is essentially a strategic imperative. The term’s downside, however, is that it implies maintaining the status quo in terms of rates of supply rather than surging in anticipation of new or larger operations. Despite this, retaining the term “sustainment” is preferable to inventing a new buzzword, such as “just-in-time” logistics or “precision” logistics, which often draws more attention to the term than to the idea behind it. 

It might be useful, however, to distinguish between “operational sustainment,” referring to logistics within the theater of war, and “strategic sustainment,” referring to logistical flow outside, or up to, the theater of war. A reliable logistical flow lends credibility to U.S. security guarantees, giving strategic sustainment a political value that in some cases exceeds its military value. Conversely, gaps in U.S. supply chains, or the penetration of those chains by nefarious actors, can undermine Washington’s credibility. What’s more, strategic sustainment offers critical political leverage because it enables Washington to adjust the logistical flow to influence the actions of allies and partners.

U.S. policymakers should have brought U.S. industry leaders into strategic discussions long ago. Plans should have been made and updated periodically, just as U.S. combatant commands do with military contingency plans. Elevating sustainment to a strategic imperative can help avoid such gaps in the future while at the same time furthering the integration of America’s defense industrial base with U.S. national security strategies. As the joint force’s principal proponent for operational sustainment and the service typically responsible for providing logistical support to America’s multinational partners, the U.S. Army should be the loudest voice promoting that integration both at home and abroad.


The brewing sustainment crisis reveals a serious weakness, even a credibility gap, in the U.S. Defense Department’s concept of integrated deterrence. Simply put, America’s defense industrial base has not been fully integrated into Washington’s defense and deterrence strategies — which has in turn led to a production gap. The gap has occurred despite more than two decades of theorizing about and wargaming various branches and sequels of great-power competition in the European and Pacific theaters. 

The West may develop as many theories of defense and deterrence as it likes, but as history has shown, production capacity coupled with the capability to deliver war material wherever it is needed (strategic + operational sustainment) can go a long way toward winning wars. The ability to win wars, moreover, aids in deterring them. Achieving integrated deterrence, in other words, will require an integrated defense.

In sum, the future of large-scale combat operations obviously depends on the future of strategic and operational sustainment. Therefore, the Army should better synchronize Field Manual 3-0 and Field Manual 4-0. The latter especially should help close the gap between strategic and operational sustainment by elevating logistics to a principle of war, just as America’s chief allies (and foes) have done. The former document should be revised with respect to its assumptions about the availability of U.S. logistics in order to explore alternate situations. 

This does not simply mean that the United States should begin mindlessly mass-producing war materiel or ignore other challenges like ensuring the joint force has sufficient mobile logistics. Rather, it is an argument for better integration of the defense industrial base with U.S. national strategies — with the Army’s logistical expertise at the center. Rather than conclude the era of offensive maneuver is over, it is time to bring logistics back into discussions of large-scale combat operations.



Antulio J. Echevarria II is a professor of strategy at the U.S. Army War College and the editor-in-chief of the U.S. Army War College Press. He has published six books on strategic thinking, the most recent of which is War’s Logic: Strategic Thought and the American Way of War (Cambridge University Press, 2021). He is currently researching strategic insights from the war in Ukraine. 

Image: U.S. Army photo by 1st Lt. Stephanie Snyder

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