Admiral Jacky Fisher, the Royal Navy’s first sea lord a century ago, once quipped that “history is a record of exploded ideas.” Oftentimes, that’s a good thing. Detonating strategic ideas that were bad to start with—or good but senescent ideas that have been overtaken by time or technology—helps armed forces stay in tune with the times.

Fisher knew whereof he spoke. Sail gave way to steam during his lifetime, wooden to steel hulls, short-range cannon to rifled guns lofting explosive projectiles against distant foes. With the advent of the torpedo, super-empowered small craft like submarines could strike at the battleship, long the mistress of the seas. Technology opened up new tactical and operational vistas—exploding any number of time-honored methods of sea combat.

A century hence and an ocean away, a few ideas about sea power could stand some Fisheresque demolition of their own. Few things are scarier than a fallacy that commands an influential following—especially when that following resides within policy circles or, at times, the ivory tower.

The fallacies cataloged below aren’t completely wrong or meaningless. But they mislead when ripped out of strategic context—as they typically are. They exaggerate U.S. naval strength vis-à-vis likely antagonists. Policy makers who accept them could heave a sigh of relief about America’s staying power in far-flung regions—and scale back on their navy’s seemingly insurmountable margin of supremacy.

Once transcribed into accepted wisdom—and thence into entering assumptions for debates over strategy, operations, or hardware—such factoids could misshape American strategy in maritime Asia to disastrous effect. Call it a paradigm shift gone wrong. Herewith, my list of three fallacies about U.S. sea power:

1. He who spends the most wins:

How many times have you heard some commentator affect a world-weary air, observing that America spends more on defense than the next X countries combined? X usually equals ten or upwards. The implication—wink, wink, nudge, nudge—is that U.S. military supremacy remains unchallengeable, and that anyone who says otherwise is merely try to milk the taxpayers for more money.

Though superficially plausible, this analysis collapses upon close scrutiny. For one thing, military victory is not a commodity. He who spends the most need not win. Depending on whose figures you prefer, the weaker contender wins about one-third of the time in armed conflict—often by outlasting the strong. Iraq or Afghanistan, anyone? Furthermore, it costs the United States far more to deploy a unit of combat power in a regional antagonist’s backyard than it costs that antagonist.

To compound this cost mismatch, Washington confronts far more demands on its finite resources than any local opponent does. Sure, prospective foes such as China and Iran may spend a fraction of what the United States does on the military. But so what? They only care about a fraction of the earth’s surface, whereas the U.S. military manages events across the globe.

China, for instance, mainly covets supremacy within the first island chain—that is, within a small subset of the world’s oceans. Iran mostly wants to dominate the Persian Gulf, an inlet in the broad Indian Ocean. Global commitments demand a big budget, lesser commitments less so. Small wonder China and Iran can challenge U.S. primacy in Asia’s peripheral seas on the cheap. They can exert themselves to the fullest in their immediate environs. Outsiders generally cannot.

The size of the U.S. budget notwithstanding, the exigencies of worldwide operations discourage Washington from concentrating military might at any one place on the map. It could sacrifice pressing interests in, say, Europe for the sake of facing down China or Iran. Dispersal of force thins out American strength. Indeed, the U.S. military contingent on scene could find itself weaker than the combined weight of an adversary’s forces—even while the U.S. military remains bigger and more powerful in total.

This is the logic of local supremacy—a logic that served America well a century ago, when it was a regional power on the rise squaring off against stronger yet distracted powers such as Great Britain or Imperial Germany. Plus, opposing forces need not venture far from home. The fraction of the world’s oceans and seas these would-be hegemons care about adjoins their shores, whereas U.S. forces must traverse thousands of miles of potentially contested waters and skies merely to get into the fight.

U.S. forces thus need foreign bases to sustain forward operations, whereas local competitors have bases on their own soil and can get by with shorter-range—and thus less pricey—ships and aircraft. Cost/benefit logic, then, works on the home team’s behalf in countless ways. Washington must pay a premium to shape events off far-distant shores. That narrows the seemingly huge budgetary chasm between the competitors—perhaps into irrelevance.

2. The navy that bulks the most wins:

We also hear that the U.S. Navy is “bigger” than the next X fleets combined. And indeed, size matters in naval warfare. Like other factoids, this one is helpful when taken in context. It’s inert if not valueless without it. The context is that this refers to tonnage, not numbers of ships, combat capacity, or other indices used to measure a navy’s fitness to achieve tactical and operational goals. And the capacity to achieve larger goals is the only standard for measuring military might.

Tonnage—a ship’s displacement, a rough proxy for its size—does tell us some things. Larger men-of-war can carry more fuel, ammunition, embarked marines, what have you. These are essential attributes for navies that venture across the oceans to do battle on others’ turf. Fuel equips vessels for long voyages. Ammunition provides them some staying power should war break out. That’s a must considering how burdensome it is to rearm at sea.

So tonnage is necessary for a global fleet like the U.S. Navy, but it’s far from sufficient as a yardstick for combat prowess. If it were, merchantmen like the Maersk Line container vessel Emma Maersk would constitute the world’s strongest warships. After all, she displaces about five times as much as an American nuclear-powered aircraft carrier. It’s clearly absurd to crown the unarmed Emma Maersk queen of the seas. But it’s the kind of absurdity you encounter if you use tonnage as shorthand for naval power.

Other indices of capability clearly count. There’s no substitute for comparing armaments, sensors, embarked aircraft, and the other attributes that give warships and fleets advantages over their rivals. Admittedly, this is messier and more ambiguous than reciting one-liners about tonnage or numbers of hulls. But it’s also a surer guide to designing forces, tactics, and operations.

3. Navies only fight navies:

The problem goes beyond mere bulk, though. Analyses of regional military balances often assume the whole of the U.S. Navy will face off against the whole of an enemy navy. Or that’s the sense you get when commentators count up inventories of ships and proclaim that the United States will be the victor should the balloon go up. So long as the U.S. Navy inventory boasts more vessels than likely competitors, it must be good to go. Right?

Well, not necessarily. In all likelihood a fraction of the U.S. Navy will go up against the combined might of the enemy’s navy, air force, and perhaps even army. For instance, the Japan-based Seventh Fleet, totaling 60-70 warships, may enter the lists against the People’s Liberation Army Navy, and PLA Air Force warplanes equipped to operate over water, and the PLA Second Artillery Corps, the ground-force contingent that deploys China’s force of anti-ship ballistic missiles.

And if Washington decides to concentrate strength in East Asia? U.S. Pacific Fleet reinforcements must steam westward across thousands of miles of potentially contested expanses just to get into a fight. Atlantic Fleet reinforcements must swing through the Panama Canal into the Pacific Ocean, or undertake the long journey through the Indian Ocean into the Far East. These are no easy tasks—especially when confronting an antagonist bent on thwarting America’s plans.

An opponent’s battle fleet, then, may not measure up to the U.S. naval contingent on a ship-for-ship basis. But it can offset its deficiencies. Missile-armed submarines and fast patrol boats can act as offshore pickets, punishing or deterring opponents—potentially without a battle fleet’s ever leaving port. Armies like China’s can strike out to sea with anti-ship cruise or ballistic missiles. Air forces field missile-armed combat aircraft capable of venturing hundreds of miles seaward.

Best of all for a nuclear-armed defender, its land-based forces are largely off-limits to counterstrikes—unless Washington is prepared to risk escalation to a doomsday scenario. This is the crux of the debate over Air-Sea Battle, “offshore control,” and other operational concepts floating around in recent years. How can the United States deter or defeat a regional antagonist when a major part of that antagonist’s sea power enjoys a safe haven within the motherland?

In short, land-based sea power constitutes a great equalizer for a coastal state determined to fend off adversaries from nearby waters and skies. Cracking open that copy of Jane’s Fighting Ships and counting numbers of hulls, aggregate tonnage or other partial measures of naval efficacy is apt to lead navy-watchers—and, more importantly, those who decide what platforms to fund, how to configure them, and how many to order—astray.