The Buzz

Pearl Harbor: Why Japan Attacked (And Why It Was Such a Big Mistake)

This is a roundabout way of getting to the beginning. Let’s ask “what if?” as we look back seventy-five years to the Japanese aerial assault on this place. Now, as a Naval War College professor of strategy, I am required to mention our patron saint—our holiest of holies, the German military theorist Carl von Clausewitz—every time I give a talk like this one. So here’s a pearl of wisdom from the great Carl: no fair Monday-morning quarterbacking!

To learn from past failures, in other words, it’s not enough to second-guess what commanders or statesmen of bygone ages did wrong amid the fury of war. To truly learn from them, we have to envision some alternative course of action that would have yielded better results than the one they took.

Makes sense, doesn’t it? No one likes the armchair QB in New England, my adopted home, who takes Bill Belichick or Tom Brady to task for substandard play in a Patriots defeat. The natural response—the Clausewitzian response—is to ask: okay, what would you have done better, wise guy? Or if you prefer your rejoinders more highfalutin, my hero Teddy Roosevelt proclaimed that it’s not the critic who counts, but the man in the arena, splattered with sweat and blood but getting it done. And then we would subject the armchair QB’s proposed alternative to the same scrutiny we used to vet the play that actually was run.

Who knows? Maybe we would make ourselves better play-callers than Belichick or Brady through this learning process—a process we at the Naval War College call “critical analysis.”

So let’s play critic. Let’s look at Japanese failures in strategy, and then consider the strategic import of Japanese tactical failures once Tokyo did send Admiral Chūichi Nagumo’s aircraft-carrier task force hurtling toward Hawaii on its errand of destruction. Japan erred by attacking Pearl Harbor—then it erred in how its aviators attacked Pearl Harbor.

First consider the failure of Japanese strategy as strategy. What did Japanese want in the Pacific? To oversimplify, they wanted to partition that ocean between Japan and the United States. The waters, skies and landmasses west of Asia’s “second island chain”—a loose line of islands stretching from northern Japan through Guam down to New Guinea—would become a Japanese preserve.

To accomplish such an ambitious goal, the resource-poor island state desperately needed imports of raw materials—primarily from Southeast Asia. That lent even more momentum to Tokyo’s plans for aggression.

In effect, then, Tokyo envisioned enclosing its territorial conquests and sources of natural resources within a long, distended defense perimeter that coincided, more or less, with the second island chain. It would barricade them off from outsiders. Now, Japanese strategists had seen the United States as the next likely enemy in the Pacific since shortly after the turn of the century. The Imperial Japanese Navy had eradicated Chinese sea power during a short, sharp war in 1895, then turned around and crushed the Russian Navy in naval battles in 1904 and 1905—putting an end to Russian sea power in the Far East for decades to come.

That left the United States Navy as the next big thing for Japan’s navy. Japanese strategists set to work determining how to overcome another strong yet faraway foe—just as U.S. naval strategists in places like the Naval War College pondered how to project military might into a determined opponent’s home region, thousands of miles from American shores.

Think about what Japan was contemplating from a geographic and geometric perspective. Every time Japan extended its defense perimeter eastward or southward was like extending the radius of a circle: it expanded the sea area Japan’s fleet had to police by the square of the distance from the Japanese home islands, which lay at the empire’s center. And perversely, Tokyo had an insatiable appetite for more sea space. It was constantly extending the defensive frontier—including at far-flung places like Guadalcanal, in late 1942. The circle got bigger and bigger, Japanese naval coverage thinner and thinner. The Imperial Japanese Navy’s reach exceeded its grasp by mid-1942—just as Yamamoto had foreseen.

But the problem was worse than policing vast sea areas: trying to defend a long defensive line is hard, at sea or on land. Think about it. If I want to defend a line, I have to be stronger than my opponent at every point along the perimeter. That verges on impossible. By contrast, my opponent only has to be stronger than me at one point along the line. He can mass forces at some point along the line and punch through. There’s no such thing as an impenetrable defensive wall sprawling across hundreds or thousands of miles. That’s a fallacy.

In short, Japan had put itself in an impossible position unless it could keep the U.S. offensive halfhearted. And it could have. Clausewitz teaches that the elements of strength are force—by which he means material resources—and will. A combatant like the United States can boast all the economic and industrial resources in the world, yet remain militarily weak if it lacks the resolve to tap those resources, converting latent into actual military might.

Japan, in other words, could weaken America by being less provocative than it was. It could avoid firing Americans’ passion for war, and thus their desire to construct and deploy a vast military machine. Japan probably had to attack U.S. possessions to get its way, but it could have attacked something Japan valued but the American people and their leaders did not: the Philippine Islands. Few back home could find the Philippines on a map. It’s doubtful an assault confined to the Philippines would have stoked the popular fury set loose by the raid on Oahu.