Offshore balancing: a superior U.S. grand strategy! Unless you try to execute it—in which case doubt abounds. A strategy that’s not actionable is no strategy at all.

Over at Foreign Affairs, nevertheless, University of Chicago professor John Mearsheimer and Harvard professor Stephen Walt are back with their latest manifesto on behalf of offshore balancing. They’re nothing if not indefatigable. Read the whole thing and hurry back.

In a nutshell, offshore-balancing proponents beseech U.S. leaders to offload less-than-pressing commitments onto powers that inhabit contested rimlands; retire from those rimlands, trusting to the “balancing” logic that beguiles scholars of “realist” leanings to keep the peace; and go back only when local powers prove incapable of keeping some overbearing neighbor in check.

The conceit is that states take league to resist would-be hegemons—and usually succeed. The gods of strategy help those who help themselves.

Professors Mearsheimer and Walt improve on most entries in the offshore-balancing genre. They say they want to preserve American primacy, both within the Western Hemisphere and preferably across the globe. They admit that—in certain extreme circumstances—Washington must forward-deploy “enough firepower to the region to shift the balance” in friendly powers’ favor. U.S. forces, then, may have to be onshore before the outbreak of war to steady the equilibrium.

And, in a passage sure to warm the hearts of Asia hands, the coauthors aim their strategy at one particular would-be hegemon. Mearsheimer and Walt entreat American leaders to undertake a “major effort” to offset a domineering China that’s accumulating the trappings of great power. Good stuff.

Part of that effort must be to halt China’s effort to rewrite the rules of the maritime legal order in the South China Sea, laying claim to a massive swathe of the global commons and its neighbors’ exclusive economic zones. How America could accomplish that from what amounts to an offshore stance—with the forces that would accomplish it stationed mainly in Japan, far to the north—remains an open question. If anything, Washington needs to boost its forward presence in Southeast Asia following last week’s ruling from the International Tribunal for the Law of the Sea, which put an end to Beijing’s claim that regional waters belong to China by right.

A China thus stung could prove tough to deal with. Accordingly, the coauthors’ approach marks a welcome turnaround from two years ago, when Mearsheimer, in the latest edition of The Tragedy of Great Power Politics, pronounced it a “fact” that “present-day China does not possess significant military power.” That was far from true in 2014. It’s less and less true every day, as the People’s Liberation Army amasses armed might at sea and aloft. Credit Mearsheimer in particular for amending his views to keep pace with the times.

Especially given the concept's appeal. Offshore-balancing logic is seductive if not compelling in some respects. Concentrating effort—measured in manpower, resources of assorted types, policy energy—where it matters most is Strategy 101. Yet great powers commonly flout such teachings. They take on commitments willy-nilly, forgetting that even the mighty have limits. A great power accomplishes little if it tries to do everything, everywhere, all the time. Indiscipline attenuates its power. Economizing on commitments, by contrast, permits statesmen and commanders to deploy finite assets at a manageable number of places on the map, making themselves strong where it counts.

All that notwithstanding, great-power leaders find it hard to prune back commitments, complying with prudential logic. Why? Allies clamor for support. Theaters, campaigns, and issues attract constituencies within the foreign-policy apparatus. Constituents see “their” enterprises as commanding paramount importance, and loudly oppose cutbacks. Politicking deflects strategy making from a purely rational course.

But beyond all that, the logic of great power exhibits a ratchet-like character. Seldom do statesmen cancel commitments. Doing so, they fear, would annul their credibility as trustworthy allies, and potentially shatter the whole imperial enterprise. Historians make much of Great Britain’s pre–World War I retrenchment in the Americas and the Far East, where London negotiated understandings with local powers to safeguard its interests, precisely because shedding burdens is so rare in history.

Husbanding strength for genuinely crucial endeavors, then, is at once essential and perversely difficult. Restoring discipline to American strategic thought represents a worthwhile cause.

Enough with the plaudits, though. Like “restraint” and other catchy slogans commonplace in foreign-policy debates, offshore balancing is less a strategy than an attitude toward strategy. That’s probably why Mearsheimer and Walt, like other offshore-balancing proponents, are coquettish about how they would prosecute their strategy.

Small wonder officials and scholars from contested regions like Northeast Asia fret about offshore balancing should Washington embrace it. Japanese, Koreans and many others fear it portends an American retreat. They fear Washington will vacate defense pledges of decades’ standing without any viable plan for coming to friends’ rescue when times grow dire.

They should worry. It’s easy to withdraw from foreign bases, but hard to go back. It only makes matters worse when offshore balancers soft-pedal nettlesome details—details such as how Washington will remake alliances after abandoning the allies, or how U.S. forces will fight their way into embattled regions through a thicket of anti-access defenses, or how Washington intends to keep the peace while resuming an offshore posture afterward.

In short, offshore balancers’ hearts are in the offshore part—the balancing part is secondary for them. Hence their inattention to the mechanics of intervening in Eurasian rimlands.

Mearsheimer and Walt also appear indifferent to America’s guardianship of the international system. They backhandedly acknowledge the relationship between a forward position and economic vitality, only to discount the system’s need for a custodian.

They do so amid what amounts to a series of conversations with straw men advocating alternative grand strategies. Straw men say the darnedest things. Some, contend the coauthors, hold that “the U.S. military must garrison the world to keep the peace and preserve an open world economy.” This they deem “unconvincing.”

And no wonder. But who is it who says America must “garrison the world” to supervise the globalized system? The coauthors don’t say. If someone went on record saying such a thing, they would presumably quote him and hang him by his words.

Even so, the coauthors retort only feebly to the strawman they set up. They do so through alt-history, claiming that keeping U.S. forces in Europe after World War I wouldn’t have halted Hitler’s war making. After all, an “unshakable desire for war” impelled the Nazi tyrant. An offshore stance, then, was as good as an onshore stance during the interwar decades.

So it seems their account of offshore balancing in World War I runs something like this: the Wilson administration intervened in a system-shattering war late in the fighting, earned a dominant say at the bargaining table, and fashioned a peace settlement convivial to its aims. The United States then walked away, refusing to help enforce the settlement for which American arms had fought. And that’s a good thing, since staying in Europe would have done little to preserve the postwar order anyhow.

This is the model of U.S. grand strategy that Mearsheimer and Walt want the United States to adopt? Consider how suspect their counterfactual history is. Hitler confessed that France could have stopped him as late as 1936, when he ordered the Rhineland remilitarized. The tyrant recalled that “if the French had marched into the Rhineland, we would have had to withdraw with our tail between our legs, for the military resources at our disposal would have been wholly inadequate for even a moderate resistance.”

So, it seems, France—disheartened, and bereft of allied support—could have stopped Hitler’s rise all by itself in 1936. Are we really to believe that a France backed and emboldened by allies would have been unable to abort Hitler’s rise, or prevent it altogether? C’mon. Retreating offshore worsened things.

Today, while the United States can’t and shouldn’t garrison the world, it had better maintain overseas bases to police far-flung oceans and seas. Mearsheimer and Walt say next to nothing about how the United States can act as keeper of the system of maritime trade and commerce from the Western Hemisphere, or who will preside over freedom of the sea if the American sea services—the U.S. Navy, Marine Corps and Coast Guard—withdraw to home waters and relinquish that function.

Here’s what some, ah, real partisans of a forward U.S. posture would say about the global economy. Trade travels overwhelmingly by sea. A menagerie of pirates, gunrunners and traffickers of all sorts—not to mention hostile states—menaces the shipping lanes. Trade and commerce, and in turn economic prosperity, will suffer unless some strong seafaring power keeps the global commons safe for merchant and naval traffic.

Freedom of the sea is not self-enforcing. Someone has to enforce it. If not America, who? Europe, where naval strength is in freefall? China, a false friend to maritime liberty? Russia?

Doubtful. But if America remains the enforcer, exactly how can the sea services police embattled waters without naval stations nearby? They can’t. Bases constitute one of three struts of sea power (the others being shipping and commerce). Knock out that strut and sea power collapses.