Here's What You Need to Remember: Sino-Japanese war could break out over matters Westerners deem inconsequential. It would be a coalition war, and it could be big, bad, and long. The US-Japan alliance might appear solid in the early going, obscuring subterranean fractures within the alliance. Yet transpacific unity might dissipate should the struggle wear on and American resolve flag -- exposing these fissures.

Let's not understate the likelihood of war in East Asia or kid ourselves that the United States can remain aloof should China and Japan enter the lists. It's tough for Westerners to fathom the nature of the competition or the passions it stokes. From an intellectual standpoint, we have little trouble comprehending the disputes pitting the Asian rivals against each other. For example, both Tokyo and Beijing claim sovereignty over the Senkaku/Diaoyu Islands, a tiny archipelago near Taiwan and the Ryukyus. China covets control of offshore air and sea traffic, hence its new East China Sea Air Defense Identification Zone (ADIZ) and its efforts to rewrite the rules governing use of the nautical commons. Undersea energy resources beget frictions about where to draw the lines bounding exclusive economic zones (EEZs). And so on.

The facts of these cases are outwardly simple. They're about how to divvy up territory and stuff. Outsiders get that. But therein lies a danger -- the danger of assuming that tangible, quantifiable things are all there is to an impasse. That's doubly true when the territory and stuff under dispute command trivial worth. By strategist Carl von Clausewitz's cost-benefit logic, the Senkakus or Scarborough Shoal merit minimal time or resources from any of the protagonists. Hence commentators wonder why compromise appears so hard when the stakes are so small by objective standards. They find it baffling that great powers would risk war over "uninhabited rocks in the East China Sea.” Some Asia-watchers strike a world-weary tone at the willingness of societies to struggle over "intrinsically worthless" geographic features.

Why, they ask, can't the contenders just split the difference -- restoring regional harmony in the bargain, and sparing others needless entanglements and hardships? To cling fast to objects of little obvious value seems obtuse, if not irrational and self-defeating.

Is it? Sci-fi master Robert A. Heinlein might jest that Westerners understand these matters but don't grok them. Great questions encompass not just the concrete interests at issue but also larger principles. Heinlein coined the term grok for his classic Stranger in a Strange Land. It means "to understand so thoroughly that the observer becomes a part of the observed." It means feeling something in your gut, not just knowing it intellectually. He appeared to despair at one person's capacity to truly know another. To grok "means almost everything that we mean by religion, philosophy, and science." But such "deeper understanding," vouchsafes Heinlein, eludes most people as color eludes "a blind man." The result: an unwitting empathy deficit toward allies and prospective adversaries alike.

Yet grok grim strategic realities we must. This competition is about more than islets or ADIZs. Nothing less than the nature of the Asian order is at stake. Making the world safe for democracy, or oligarchy, or whatever regime holds power at home constitutes a basic impulse for foreign policy. From the age of Thucydides forward, nations have spent lavishly to preserve or install regional orders hospitable to their own national interests and aspirations. By surrounding itself with like-minded regimes, a nation hopes to lock in a favorable, tranquil status quo. As it was in antiquity, so it remains today. Imperial Japan upended the Asian hierarchy in 1894-1895, smashing the Qing Dynasty's navy and seizing such choice sites as Port Arthur on the Liaotung Peninsula. It began making Asia safe for a Japanese empire.

Military triumphs often underperform their political goals. But as my colleague and friend Sally Paine notes, the first Sino-Japanese War was a limited war whose effects were anything but limited. The Qing regime remained in place following its defeat, but the Treaty of Shimonoseki, which terminated the conflict, signified Japan's eclipse of China as Asia's central power. The treaty's terms -- in particular its transfer of Taiwan to Japan -- modified the regional order in ways we still live with today. Indeed, Professor Paine points out that Chinese foreign policy since 1895 has striven to repeal Shimonoseki, while Japanese foreign policy has sought to reaffirm it.

In short, Imperial Japan ousted China from its place atop the Asian hierarchy through limited war. China would like to repay the favor, regaining its rightful -- to Chinese minds -- station through similarly limited coercive diplomacy. Classical strategist Sun Tzu instructs commanders to look for opportunities to achieve disproportionate effects through minute amounts of force. Beijing evidently discerns such an opportunity in the East China Sea. It hopes to make Asia safe for its brand of communism-cum-authoritarian capitalism.

But the geometry of any future conflict will be more complex than the one-on-one Sino-Japanese War. Curiously, the United States is a not-so-silent partner in guaranteeing the remnants of the Treaty of Shimonoseki, as modified by the outcomes of the Russo-Japanese War (1904-1905), the Second Sino-Japanese War (1937-1945), and the Pacific War (1941-1945). American officials insist that Washington has no particular stake in whose flag flies over the islands and atolls dotting Asian waters. That's true. But it has a strong interest in preserving the system it has presided over since 1945.

Permitting any one coastal state to change the rules by fiat -- to abridge freedom of the seas and skies, or wrest territory or waters from another -- would set a dangerous precedent. If Beijing gets away with amending the system once, why not again and again? And if China, why not regional powers elsewhere in the world? For the United States, then, this is a quarrel not over flyspecks on the map, but over principle. That's why the Senkakus and the ADIZ matter to Americans. Call it entrapment if you must. But it's doubtful any U.S. administration could lightly abstain from a Sino-Japanese trial of arms.

So Tokyo, Beijing, and Washington all have vital stakes in this contest. What does that imply about a hypothetical war? Clausewitz urges statesmen to let the value they assign their "political object," or political aims, govern the "magnitude" and "duration" of the effort they mount to obtain those aims. The more important the goal, the more lives, treasure, and hardware a combatant expends -- and for longer. Massive interests warrant massive investment. All three Asian stakeholders thus may prove willing to spend heavily, and for a long time, to get their way.

Here's the rub: Clausewitz prophesies that each contender, mindful that it could be outdone, will apply more force than the bare minimum to avoid surrendering the first-mover advantage to the adversary. Leaders fear letting the opponent get the drop on them. Doing more, sooner, helps a protagonist stay ahead of the competition and bolster its prospects of victory. An escalatory dynamic takes hold if everyone does more than simple cost-benefit logic dictates. Washington and Tokyo should acknowledge this in their internal and joint deliberations.

Clausewitzian fatalism represents the beginning of strategic wisdom. It's safe to assume the contestants will all strive to achieve their goals through minimal force -- preferably without fighting at all. No one relishes the hazards of war. It's equally safe to assume that they see yielding territory, status, or maritime freedoms as even worse than war.

A fight over seemingly minor stakes, then, could mushroom into a major conflagration arraying China against the US-Japan alliance. How much passion would an East China Sea imbroglio rouse among the combatants? China and Japan would be all in. Disputes involving sovereignty -- particularly territory and resources -- tend to drive the perceived value of the political object through the roof. Tokyo and Beijing, moreover, are acutely conscious that the post-1895 status quo is in play. In Clausewitzian parlance, goals of such value merit open-ended efforts of potentially vast magnitude.

American fervor is the key unknown. The United States could be conflicted about its part in a protracted endeavor. It could confront a mismatch between compelling yet seemingly abstract interests, and popular apathy toward these interests. Freedom to use the global commons is indubitably a vital U.S. interest. So is standing beside friends in peril. Everyman would doubtless agree if you put these questions to him. But how many rank-and-file citizens truly grok the system's importance to their daily lives? Few, one suspects.

If so, two antagonists attaching immense value to their objectives will face off in the East China Sea, one backed by a strong but faraway ally whose commitment could prove tepid. Clausewitz -- yep, he speaks out on contemporary affairs once again -- alleges that no one attaches the same urgency to another's cause that he assigns to his own. The ally with less skin in the game makes a halfhearted commitment to the cause, and looks for the exit when the going gets tough.

If the old skeptic is right, the US-Japan alliance could come under stress in wartime. Tokyo and Washington share the same immediate goal, conserving the US-led order in East Asia. Consensus about the surroundings and how to manage them would seem to cement allied unity. But as Clausewitz reminds us, the importance assigned to a goal -- not just the goal itself -- matters. One ally can place so-so value on a goal that another prizes dearly. Tokyo has status and territorial interests at stake, riveting its attention and energies on the dispute. Yet it's far from clear that the American polity -- state and society -- values custodianship of the maritime order or the defense of Japanese-held lands that highly. Suspicions could seep into allied consultations, with Tokyo questioning Washington's devotion and Washington resenting being dragged into war.