In light of the Houthis’ much-touted agreement to stop assailing shipping traversing the Red Sea, Bab el-Mandeb Strait, and Gulf of Aden, an aviator friend writes to ask whether air power proved decisive in the irregular naval war against the Yemeni rebels.

To which I boldly say: maybe. 

    Prompting this exchange, of course, was my late March TNIcolumn siding with Admiral J. C. Wylie, who proclaimed that air power and other “cumulative,” scattershot forms of warfare never decide armed strife on their own. Wylie opines that control—generally speaking, control of key terrain or something on the Earth’s surface—is the purpose of military strategy. Bombarding something from the air is not the same as controlling it. Ground forces, on the other hand, can impose permanent, suffocating control. Ergo, air and missile forces are the “supporting” arm of ground might in any campaign. They’re an enabler, not an end in themselves.

    Wylie’s proverbial “man on the scene with a gun”—a soldier or Marine bestriding terra firma while toting heavy firepower—is the “supported” arm. The soldier is the agent of physical control, and thus the final arbiter of martial success. In other words, air power is important, but insufficient to yield victory and enforce the postwar peace. No land power, no durable results.

    Two points. First, to gauge whether some operation or campaign was decisive, it’s helpful to define what decisive means. As with so many terms in the realm of warlike affairs, there is no universally agreed-upon definition of the word. The definition we commonly use in the hallowed halls of Newport comes from Carl von Clausewitz, the military sage of nineteenth-century Prussia. Reading between the lines a tad, Clausewitz defines a strategic attack that leads “directly to peace” as a decisive undertaking. 

    There’s a world of mischief in that adverb directly. It can refer to time, meaning a strategic attack that precipitates peace more or less immediately. It could have geospatial import, meaning peace comes once key terrain, a city, or enemy forces are under control. Or both.

    But the U.S. Navy-led air and missile campaign against the Houthis did not lead to peace, either directly or otherwise. In fact, Houthi spokesmen specifically noted that attacks on Israel—the fundamental purpose of the militants’ campaign—would continue and remain unaffected by the ceasefire. Houthi rocketeers have continued lobbing missiles toward the Jewish state. What U.S. and coalition bombardment produced was a perhaps-temporary pause in a secondary effort—the assault on regional shipping lanes. Indiscriminate attacks on shipping did little to levy pressure on Israel anyway. Ending them was an easy choice.

    So the strongest defensible claim on behalf of war-winning air power in the Red Sea is that air and missile strikes induced the Houthis to curtail a part of their campaign—one that was costing them a great deal in military infrastructure and hardware, while contributing little if anything to their prime goal of coercing Israel into halting its Gaza offensive. By that standard, boosterism on aviation’s behalf is premature at best.

    Second, and intimately related, it may be that Admiral Wylie took his maxim about the indecisiveness of cumulative operations too far. Let’s consult Clausewitz again. The Prussian scribe observed that how much a combatant treasures its “political object,” or political aim, determines the “magnitude,” or rate at which it expends martial resources to obtain them, and the “duration,” meaning how long it keeps up the expenditure. Rate times time equals the total amount of something. In warfare, as in buying on an installment plan, multiplying the size of each payment by the number of payments yields the total price tag for the goal of a martial venture. And how much you want something determines how much you spend on it.

    The corollary to the Clausewitzian cost/benefit calculus is this. There is no fixed price to the political object. In fact, the enemy gets a say in the price—and will doubtless try to drive it upward. If the goal begins to cost more than it is worth to a combatant’s leadership, cost/benefit logic says the time has come to stand down and stop paying the price for it.

    Any number of developments could upset this calculus. The contender may have to expend resources at a more prodigious rate than the leadership expected. Or the campaign may drag on longer than expected. Or the leadership—perhaps itself changing over time—may stop caring about the goal as fervently as it once did. Or other, more pressing commitments may come along. In any of these cases, the political goal may come to cost more than it is worth to a combatant, and the leadership will be inclined to cut its losses rather than double down on sunk costs.

    It is far from unthinkable that aerial bombardment might pummel a halfhearted foe into submission by triggering its rational, Clausewitzian cost/benefit calculus. If the Houthi leadership came to see little value in lashing out at mercantile and naval shipping, it could truncate that part of the counter-Israel campaign, halting U.S.-led attacks while redirecting ammunition and resources to the main effort. In that narrow, partial sense, air power unaccompanied by a ground offensive may have nudged Houthi calculations toward an outcome agreeable to Washington. It decided something—even though it fell short of directly begetting peace.

    So was airpower decisive in the Red Sea?

    Maybe.