Here’s What You Need to Remember: No combatant can do everything everywhere on the map at the same time and expect to triumph. Japan, in particular, had to husband resources,

This year marks the seventy-ninth anniversary of the Battle of the Santa Cruz Islands. The battle is one of seven naval engagements that—together with hard-ground fighting on the part of the U.S. Marines and Army—make up a six-month bloodletting known to history as Guadalcanal. It’s a struggle replete with insights into martial strategy and operations.

There are three big ideas that come out of studying the Solomon Islands campaign. First of all, the physical setting may impel strategic and operational deliberations. The Solomon Islands is a chute of an island chain. Guadalcanal constitutes its southeastern terminus, while the Japanese fortress at Rabaul lay just beyond its northwestern terminus in yesteryear. The Solomons commands little intrinsic value apart from its strategic geography. It invites the greats of literature to turn eloquent phrases disparaging it. James Michener, to name one, terms Guadalcanal “that godforsaken backwash of the world.”

Yet “location, location, location” makes as good a slogan in strategy as in real estate. War is a business of positions, as the little Emperor Napoleon liked to point out. Position augmented by military power translates into strategic advantage for a site’s holder.

And the Solomons abounded in geostrategic potential during World War II. Imperial Japanese Navy warplanes based on Guadalcanal could fan out, menacing shipping steaming along sea routes connecting North America with beleaguered Australia. They could help isolate a crucial American ally in the Pacific War. They could stop the U.S. armed forces from commencing their long march up the island chain toward the Japanese stronghold at Rabaul, the Philippine Islands—which had fallen during the onslaught that engulfed Pearl Harbor—and thence toward Japan itself. And Imperial Japanese Navy warbirds could help Japan stake its claim to even more South Pacific turf.

The U.S. high command, spurred by Chief of Naval Operations Ernest King, pronounced surrendering such strategically located ground unacceptable. Admiral King agitated constantly on behalf of offensive action in the Pacific theater—and he made the Solomons his project in mid-1942. The fight in and around the Solomons would last for twenty-six weeks, from the American amphibious landings in August 1942 until the Japanese pullout in February 1943. That’s a lot of resources, manpower and time to expend on something about which you care little.

Lesson one: it may be worthwhile to undertake a campaign to deny an adversary something rather than wrest it away for yourself. If so, you surrender some strategic autonomy. You go somewhere because an antagonist precedes you there. Contenders, in short, may not get to fight on ground of their choosing. Sometimes they fight where and when they wish. Other times they fight where and when they must. And once in awhile neither combatant especially cares to contest a particular battleground. They bestride the field to deny it to each other.

Such was the case with Guadalcanal. American and Japanese forces waged a “bloody and desperate campaign” for—as historian Samuel Eliot Morison puts it—real estate that “neither side really wanted, but which neither could afford to abandon to the enemy.” It’s doubtful the U.S. leadership would have felt constrained to go to Guadalcanal had the Imperial Japanese Navy not gone there first and commenced constructing an airstrip, which was dubbed Henderson Field once it was under U.S. Marine management.

For their part, it’s doubtful Japan’s military rulers would have elevated the Solomons above their principal objective in the South Pacific, Port Moresby in Palau, had the U.S. sea services not contested Guadalcanal and Henderson Field with such ferocity.

Second, setting and enforcing priorities proves dicey in theater-wide contests, let alone in contests spanning the globe. Scatter forces across the map in smaller and smaller packets, and you render each packet weaker and weaker—perhaps subjecting each one to defeat, and dooming the force to piecemeal defeat. U.S. commanders and their political masters had to juggle not just commitments within the Pacific Ocean, but between the Pacific and European theaters.

Top political leaders had agreed to defeat “Germany first” even before America entered the war. The Germany-first covenant wrong-footed partisans of naval action in the Pacific for quarrels over how to apportion resources for what amounted to two full-blown wars—both of which commanded compelling importance.

Protagonists of the European theater had official policy on their side. They argued, in contemporary parlance, that the Allies should hold in the Pacific until they could win in the Atlantic. Only then would they turn full force to the war against Imperial Japan. “Holding” for Europeanists meant parrying Japanese blows while doing little, if anything, offensive in reply. It connoted passive defense. Doing the minimum against Japan would allow Washington to conserve manpower, military hardware and resources of all sorts to thrash the Axis in Europe.

Sometimes the highest authority has to adjudicate such disputes, and so it was in 1942–43. As Morison observes, preparations for Operation Torch—the invasion of North Africa—represented the marquee show in the Atlantic theater that fall, even while battle raged in the Solomon Islands (D-Day in North Africa came that November). In October, nevertheless, President Franklin Roosevelt overruled his Europe-first military chiefs. He instructed them to reinforce on Guadalcanal while still pressing ahead with Torch.

Offensive action in the Solomons meant foregoing a cross-English Channel invasion of France in 1943—an offensive the Joint Chiefs longed to mount.

Japanese ground and naval commanders had to balance among commitments as well. Tokyo had taken on a land war on the continent of Asia—a full-blown war in itself—alongside multiple maritime entanglements in the South Pacific. Army and navy chieftains wrangled over priorities but ultimately felt obliged to follow the U.S. Navy and Marines to Guadalcanal. The Japanese high command doubled down by the close of August, several weeks into the struggle. Military rulers downgraded Port Moresby temporarily until Japanese forces could win in the Solomons.

Lesson two: no combatant can do everything everywhere on the map at the same time and expect to triumph. Japan, in particular, had to husband resources, as it was battling a foe boasting many times its economic strength—and thus many times its latent military strength. The United States found itself in similar straits into 1943, when industry had geared up to produce war materiel in vast quantities.

Wise leaders interject themselves in strategic debates when necessary—refereeing among proponents of competing courses of action.

Lesson three focuses on a more general proposition: we err when we distinguish too sharply between “Eastern” and “Western” warmaking methods. Western commentators make much of Mao Zedong’s concept of “active defense.” Mao represents the theorist of the weaker contender, not to mention a practitioner of his own strategy—a strategy meant to help the weak turn the tables on the strong. Wittingly or not, Westerners depict him as the purveyor of some esoteric Oriental art of strategy premised on deception and guile.

And indeed, Mao does draw heavily on the writings of Sun Tzu, China’s martial philosopher of undying fame. Master Sun predicates his philosophy of warfare on being nimble, wily and deceptive. Yet Mao’s writings are no mere knockoff of Sun Tzu’s. Far from it. They owe as much to Western scribe Carl von Clausewitz as to any Asian master. Maoist active defense, for example, is about luring stronger foes onto onto one’s home ground. They have to advance across significant distances just to reach the battlefield—and overextend or even exhaust themselves in the process.

The Maoist concept derives in part from Clausewitz’s observation that the combatant that seizes the offensive at the outset of war sees its strength attenuated as its forces close in on the defender. The invader gets more and more remote from his bases. His logistics grow increasingly tenuous. The enemy, perhaps aided by partisan warfare, harries the invader’s flanks with minor tactical actions, sapping his combat power. Meanwhile the defender falls back on his own bases and sources of supply—exploiting the advantages that go to the home team protecting its home ground.

Ultimately the invader passes the “culminating point of the attack,” a crossover point beyond which the defender holds the upper hand. Reversing the balance of forces empowers the erstwhile weaker contender to take the offensive—and win a conventional trial of arms. Mao distills his doctrine of active defense from this insight. Chinese statements about strategy remind us, time and again, that active defense, a product manufactured partly in Europe, remains the “essence” of Chinese martial thought and the strategies to which thought gives rise. Maoist ideas thus represent an amalgam of purportedly Eastern and purportedly Western concepts about warlike enterprises.

Pretty Oriental, eh?

But the same works both ways. Americans involved with the Guadalcanal campaign formulated Maoist-sounding ideas for holding the Solomons. Allies such as Winston Churchill’s Great Britain preferred that the United States do as little in the possible in the Pacific theater—thus shunting the overwhelming bulk of manpower, hardware and other resources into the European theater and speeding the Grand Alliance along its road to victory. Skeptics branded Admiral King’s Pacific strategy “defensive-offensive,” evidently as a term of derision. Yet his logic was sound, and Mao would have grasped it immediately: hold if you must, wage offense as soon as you can.