The Chinese navy's surface forces are on the march. Destroyers, frigates, corvettes, fast-attack craft, and, most recently, the newly commissioned aircraft carrier comprise the surface fleet. Over the past two decades, the People's Liberation Army Navy (PLA Navy) has put to sea four Sovremenny-class guided-missile destroyers procured from Russia, along with ten new classes of indigenously built destroyers and frigates. Some of the latter ship types have entered serial production, adding mass to the fleet. This is an impressive feat by any standard.
The PLA Navy's metamorphosis from a coastal defense force into a modern naval service has riveted the attention of the U.S. defense community. In 2009 the Office of Naval Intelligence — a body not known for hyperbole — described the advances of China's surface fleet as "remarkable." Similarly, the Pentagon's most recent annual report on Chinese military power notes the "robust" buildup of PLA Navy major combatants since 2008.
The Liaoning carrier understandably captures the public imagination. But the true vanguard of the PLA Navy's prowess will be its surface combatants — the workhorses of any navy — that will make China's turn to the seas felt in maritime Asia and beyond. In the coming years, these warships will serve as pickets guarding the carrier, project power on their own in surface action groups, maintain a visible presence in disputed waters, defend good order at sea in distant theaters, and conduct naval diplomacy around the world. 
Yet debate persists over this metamorphosis. Skeptics doubt the PLA Navy will translate its growing material heft into real combat effectiveness. One sanguine view holds that the U.S. Navy surface fleet is more than a match for any rival in the contest for sea control — the arbiter of any naval war — and will remain so for the foreseeable future. The implication is that while Beijing may be able to exact a price from the U.S. Navy for attempting to use the seas and airspace in China's environs, the United States will still command the seas when the chips are down. 
At the tactical level, this comforting narrative holds that U.S. naval forces remain able to land a devastating blow before opposing warships get close enough to fire their first shot. In a fleet-on-fleet engagement, for example, carrier-based warplanes would unleash missiles at enemy surface combatants from standoff distances, meaning beyond the engagement range of the opponent's anti-ship arsenal. This scenario conforms to the longstanding American doctrinal preference for shooting the archer before the archer can let fly his arrow.
This tactical and technological margin of superiority will endure and perhaps even widen, so goes this storyline, letting the U.S. Navy retain its dominant position in maritime Asia.   
We're not so sure.
For one thing, China's surface fleet is quickly catching up. Mariners are cementing core competencies while closing the capability gap. For years, Chinese ships' lack of sophisticated area-wide air defenses exposed them to air and missile attacks. This shortcoming reaffirmed U.S. commanders' conviction that carrier aviators would handily defeat the PLA Navy in a fight. Now, however, near-state-of-the-art systems on board some Chinese combatants outrange the anti-ship weaponry sported by U.S. aircraft. The Luyang-class guided-missile destroyers are apparently equipped with phased-array radars similar in appearance — and, according to Chinese pundits, in capability — to the American Aegis combat system, a combination radar, computer, and fire-control system that can detect and target multiple aircraft simultaneously at long range.
At the same time, the PLA Navy has armed its warships to the teeth with a family of Russian- and Chinese-made anti-ship cruise missiles (ASCMs) boasting ranges of 120-130 nautical miles. The only comparable weapon in the U.S. inventory is the nearly-four-decade-old Harpoon anti-ship missile, whose advertised striking range is less than 70 nautical miles. In other words, major Chinese combatants can not only keep U.S. aircraft at bay, but can also close in on the U.S. fleet to unleash volleys of ASCMs outside the weapons range of U.S. vessels. Not American but Chinese archers may now hold the initiative.
Thus both the defensive and offensive sides of sea combat are stacking up in China's favor — progressively eroding the tactical advantages of U.S. naval power.
Furthermore, it is unclear whether the U.S. Navy's surface battle capacity has kept up with the times. Since the Cold War, the navy has grown accustomed to operating in uncontested waters. Indeed, directives from on high stated that no one was likely to dispute American command of the sea. Owing to such strong bureaucratic signals, the surface fleet has let the skills and hardware for striking at sea atrophy. Why practice fighting for something no one can dispute?
Other missions have preoccupied the service since the Cold War. Naval aviators have spent the past decade supporting ground forces rather than girding to duel enemy armadas. Dropping smart bombs on insurgents and terrorists in Iraq and Afghanistan demands different skill sets from evading enemy defenses and pummeling enemy men-of-war. Meanwhile, guided-missile destroyers have been burdened with an ever wider array of missions, including ballistic-missile defense (BMD). Competing missions — some of which, like BMD, command national-level scrutiny — siphon finite resources, crews' attention, and, equally important, physical space aboard ship away from the combat function.
In effect, then, the service has demoted war at sea, the raison d'être for any navy, to secondary status. Both the hardware (weaponry, sensors, and hulls) and the software (training and exercises) for sea control have doubtless suffered as a result. In an era of tight budgetary constraints, reversing two decades of steady decline in surface warfare will be neither easy nor quick. In short, prevailing assumptions about American naval supremacy are coming under strain.
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It would be a grievous mistake, nonetheless, to concentrate wholly on the operational progress the PLA Navy surface fleet has made or the tactical travails that could hold back the U.S. Navy surface fleet. Competition is about more than just gee-whiz weaponry or comparing entries in Jane's Fighting Ships. The only meaningful standard by which to gauge a seagoing force's adequacy is its ability to muster superior combat power at the decisive time, at the decisive point on the nautical chart, against the strongest probable adversary. As a great man once proclaimed, there is no substitute for victory.
It is far from clear that the United States retains its accustomed supremacy by that unforgiving standard, any more than it does in technological terms. For a variety of reasons — distance from the theater, the consequent need for forward bases and logistics fleets, expensive weaponry, salaries, and pensions — it costs the United States far more than China to stage a unit of combat power at a given place in maritime Asia. Whether the Pentagon can afford to mount superior strength in a rival great power's backyard, whether the sea services are investing in the right people and hardware to constitute that strength, and whether American seafarers have the requisite skills to prevail when battle is joined are the only questions worth asking.
That casts U.S.-China competition in a whole new light, doesn't it? A purely fleet-on-fleet engagement is improbable within the China seas or the western reaches of the Pacific Ocean. In those expanses, Beijing has the luxury of throwing the combined weight of Chinese sea power into a sea fight, dispatching not just its surface fleet but missile-toting submarines and swarms of patrol craft. Furthermore, land-based implements of sea power can strike a blow in any fleet action that takes place within their combat radii. PLA Air Force warplanes can join the fray, as can anti-ship missiles fielded by the PLA Second Artillery Corps. Lord Nelson, who knew a thing or two about operating fleets under the shadow of shore-based weaponry, sagely counseled that a ship's a fool to fight a fort. That's doubly true today, when Fortress China can reach scores or hundreds of miles out to sea.
One part of the U.S. Navy, then, could conceivably confront the whole of China's maritime might. The U.S. sea services are dispersed throughout Asia and the world. To estimate the outcome of a fleet action, we thus have to determine how the contingent the U.S. Navy is likely to commit to battle — including its aerial and subsurface components, along with any assets supplied by allies like the Japan Maritime Self-Defense Force or South Korean Navy — stacks up to the massed power of the PLA Navy fleet, backed by the array of anti-access weaponry at PLA commanders' disposal. (This assumes Chinese commanders do the smart thing in wartime and mass their fleets for action.) If China's navy outmatches the U.S. or combined fleet contingent under such conditions, it is adequate to the tasks entrusted to it by the political leadership. If not, the advantage resides with the United States and its allies.
The unenviable task before Washington, then, is to preserve or extend the margin of superiority of part of its naval force over the whole maritime force, sea and land, that's available to Beijing. It's tough to pull off such a feat, especially under present circumstances. Finances are straitened. Overall numbers are under stress as a result, as is the military's capacity to innovate. To make ends meet, the U.S. Navy is substituting light combatants such as the new Littoral Combat Ship for multi-mission warships bristling with heavier firepower. To compound these problems, the fleet finds itself outranged by its most likely antagonist. It will be several years before a new anti-ship missile restores long-range hitting power to the fleet, or until exotic armaments such as electromagnetic rail guns or shipboard lasers augment the main battery.
From a grand-strategic standpoint, the lag in weapons development could open a danger zone in which Beijing is tempted to strike before its range advantage lapses. Imperial Japan made a similar now-or-never calculation in 1904, realizing that rival Russia was constructing new battlewagons for its Pacific squadron. It struck before St. Petersburg could amass insuperable strength in Far Eastern waters. In 1941, likewise, Tokyo hit the U.S. Pacific Fleet before the entirely new fleet being built under the Two-Ocean Navy Act of 1940 could arrive in the theater and shift the naval balance against Japan. U.S. and allied leaders must remain watchful, lest Beijing too succumb to the temptation to settle disputes around its nautical periphery by force.
Are submarines the great equalizer, a U.S. Navy game-changer akin to the "assassin's mace" that so beguiles Chinese strategists? Many Westerners appear to think so. They consider undersea warfare a talisman, assuming that the U.S. Navy can simply dive beneath the waves and pummel the PLA Navy from below. Submariners voice confidence in the superiority of American and allied boats over anything China has put to sea. We see no reason to question the allies' qualitative superiority in this sphere, and indeed we have depicted the subsurface fleet as a core competitive advantage for the United States.
But while quality remains on the allied side, numbers are more problematic. Yes, under the pivot to Asia, sixty percent of the U.S. Navy’s 72-vessel submarine force now calls the Pacific Ocean home. But 18 of those 72 submarines are Ohio-class ballistic- or cruise-missile boats (14 SSBNs, 4 SSGNs) meant for shore bombardment. That leaves 54 attack submarines (SSNs) suitable for a tilt against the PLA Navy, sixty percent (32-33 submarines) of which will be in the Pacific. That may sound like a lot, but bear in mind that no unit is ready for service all of the time. Routine upkeep, extended overhauls and refueling, crew rest, and training all have claims on a vessel's schedule.
A hoary U.S. Navy axiom holds that it takes three ships to keep one on foreign station. One is in the shipyards and completely out of service, another is preparing for deployment, and the third is actually on cruise. If anything, the 3:1 ratio actually overstates the proportion of ships available for combat duty.  Even using this ratio, however, U.S. naval commanders can expect to have 11 fully combat-ready subs at their disposal at any time. Assuming the rhythm from overhaul to deployment holds up, another 11 may be available in varying states of readiness.
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Twenty-two SSNs, no matter how good individually, is a slender force to cover the China seas and Western Pacific in wartime. Theorist Julian S. Corbett advises commanders to post vessels at the origin of an enemy fleet's voyage; at its destination, if known; or at focal points such as straits where shipping has to congregate as it passes from point A to point B. Otherwise it may be hard to make contact. Monitoring Chinese seaports, along with narrow seas such as the Luzon Strait and the passages through the Ryukyu Islands, will stretch the tactically proficient but lean U.S. submarine fleet. That in turn will leave broad operating grounds open to the PLA Navy.
Undersea warfare, then, remains an advantage, owing not just to American skill but to the PLA Navy's neglect of antisubmarine warfare. But the U.S. Navy needs more mass — meaning more boats — if it is to vanquish China's navy from the depths. Practitioners and pundits err if they view the silent service as it currently stands as a panacea. Doubling the submarine force would be a prudent move for Washington in its strategic competition with Beijing.
Where does all of this leave us? It's commonplace among China-watchers to make the U.S. Navy the benchmark by which to judge the PLA Navy's size and composition. This misleads. As noted here, the proper yardstick is the navy's capacity to fulfill the goals assigned to it by political leaders, in the expanses that matter, against the strongest likely opponent. Beijing's immediate goals and its likely opponents fall within reach of the abundant shore-based armaments festooning Fortress China. Combining land- with sea-based implements of marine combat yields a force far more formidable than side-by-side comparisons of surface fleets would indicate. The PLA Navy, then, may not need a surface fleet symmetrical with the U.S. Navy's — in terms of flattops, air wings, destroyers, etc. — to get its job done.
Observers must apply standards unique to China to determine whether China's Navy has struck the right balance of capabilities. Comparing it to a globe-spanning navy like America's reveals little.
Toshi Yoshihara and James Holmes are professors of strategy at the U.S. Naval War College, where Yoshihara occupies the John A. van Beuren Chair of Asia-Pacific Studies. The views voiced here are theirs alone.