Summary and Key Points: Ukraine’s offensive into Russia’s Kursk district, though daring, risks violating strategic principles from both Clausewitz and Sun Tzu. Clausewitz’s "Three R's"—reward, risk, and resources—dictate that a secondary theater should only be opened if it offers exceptional rewards without jeopardizing the primary front.

-Ukraine’s incursion fails to meet these criteria, as its forces face no decisive superiority in the main Eastern theater. Sun Tzu, too, while favoring indirect and fluid approaches, stresses prudence when outnumbered.

-With Russia's numerical advantage, Ukraine should focus on consolidating manpower for defending crucial territory, avoiding unnecessary risks in Kursk.

Strategic grandmasters would upbraid Ukraine’s leadership for hurling an offensive into the Russian border district of Kursk. Sure, Carl von Clausewitz, the Prussian soldier-scribe of everlasting renown, countenanced opening secondary theaters or operations under certain circumstances. But he did so grudgingly. Clausewitz cautioned commanders to divert forces only on a not-to-interfere basis with success in the primary theater, which after all represents the theater of greatest consequence as the leadership defines it.

This is sage counsel. If nothing else, strategy means setting and enforcing priorities. This takes self-discipline. It makes little strategic sense to hazard what matters most for the sake of something that matters less, no matter how beguiling. For Ukraine—a combatant that stands in mortal peril—the foremost priority must be to hold as much Ukrainian ground as possible while striving to regain lost ground. Kursk is great from a fist-pumping standpoint. Apart from that its benefits appear lackluster.

As he does for so many martial enterprises, Clausewitz enunciates a simple formula to help the leadership fathom whether to open a secondary theater or operation. Some years ago I took to calling it Clausewitz’s Three R’s, namely reward, risk, and resources. A new endeavor, that is, must not merely promise nice-to-have gains. It must be “exceptionally rewarding.” He presents no units of measurement for exceptional reward, but his message is stark: if it is not necessary to do this, it is necessary not to do it.

The notion of wresting territory from Russia exudes a certain allure on the logic that paybacks are hell, but do the prospective rewards qualify as exceptional? It’s hard to see how. If not, Ukraine’s leadership should cut the foray short.

But there’s more to the calculus than forecasting rewards. Clausewitz cautions the commander against running undue risk in the “principal theater” in order to pursue lesser aims elsewhere. And he defines risk in terms of the resources available in the principal theater. Only “decisive superiority” of resources in the main theater can justify siphoning resources into a secondary effort.

Only if a candidate theater or operation passes all three tests—Clausewitz’s Three R’s—should the venture proceed.

Does anyone think the Ukrainian armed forces command decisive military superiority over Russia in eastern Ukraine, the major fighting front? Unless they do, writes Clausewitz, Kiev is courting unacceptable risk in Kursk. In all likelihood he would fault Ukrainian military and political leaders for strategic indiscipline.

Now, it is conceivable that the classical Chinese general Sun Tzu, Clausewitz’s companion in the pantheon of arms, would not deplore the Ukrainian incursion into Kursk. Sun Tzu advises the general to take an opportunistic, highly supple approach to battlefield operations, employing “direct”—sometimes translated as “normal,” or “orthodox”—and “indirect”—sometimes translated as “extraordinary,” or “unorthodox”—lines of effort.

Direct operations generally refers to a frontal assault, while indirect operations strike the enemy’s flanks from some unforeseen axis. Sun Tzu enjoins the wily commander to be prepared to shift effort back and forth as the fortunes of battle dictate. He might make the indirect assault the main effort if the direct assault falters, and thus relegate the direct effort to secondary status. He might shift back, and back again, if circumstances warrant. Etc.

This is a fluid concept of generalship. For Master Sun there are infinite combinations and recombinations of direct and indirect effort.

On its face Ukraine’s invasion of Kursk might resemble a macro-scale indirect attack apt to warm Sun Tzu’s heart. It certainly took Moscow by surprise. But here’s the thing. Like Clausewitz two millennia later, the Chinese sage fretted constantly about risk and resources. If the general’s army boasts ten times as many soldiers as the enemy, he exhorts the general to order the foe surrounded. If the general enjoys five times the manpower, he should attack.

And so forth. As the force ratio dwindles, the less venturesome the commander can afford to be. Acting otherwise flirts with disaster. “If weaker numerically,” Sun Tzu goes on, “be capable of withdrawing.” And “if in all respects unequal, be capable of eluding him, for a small force is but booty for one more powerful.”

The Chinese strategist traffics more in maxims than in Clausewitz-esque analysis of alternative courses of action. He dispenses the wisdom of a master. But given his emphasis on numbers of soldiers, it’s tough to imagine his endorsing Ukraine’s incursion into Russia. Since 2022 the Ukrainian Army has outperformed expectations by a wide margin. That should not mask the fact that Ukraine is—and will remain—the lesser antagonist confronting a bulkier, better-resourced neighbor that sees vital interests at stake. It is weaker by most indices and must conduct itself accordingly.

Strategic prudence—from nineteenth-century Europe and ancient China alike—urges Kiev to wind down the Kursk operation, and consolidate scarce manpower and resources to defend what matters most.

Enough with the adventurism.

About the Author: Dr. James Holmes, U.S. Naval War College 

Dr. James Holmes is J. C. Wylie Chair of Maritime Strategy at the Naval War College and a Faculty Fellow at the University of Georgia School of Public and International Affairs. The views voiced here are his alone.

Image Credit: Creative Commons and/or Shutterstock.