Red tide -- James Holmes

In late July, Chinese President Xi Jinping shared his views on sea power and maritime territorial disputes. Beijing is amenable to "shelving disputes and carrying out joint development" in waters such as the South China Sea, where, according to the official line, it enjoys "indisputable sovereignty." It will employ "peaceful means and negotiations to settle disputes and strive to safeguard peace and stability," but it won't "abandon its legitimate rights and interests." Beijing asserts sovereignty over the waters, islands, and atolls within what it calls the "nine-dashed line," a line that encloses the vast majority of the South China Sea, including huge swaths of the exclusive economic zones belonging to Southeast Asian states.

Xi appears to be saying that China is prepared to postpone resolution of these disputes for the sake of working alongside Southeast Asians to tap the region's natural resources, and that it is willing to negotiate. That sounds reasonable. But he also seems to be saying that China has ruled out compromise and will continue building up its maritime strength to enforce its will. If Xi is sincere in all these statements, then the only real question left is when Asian powers will acquiesce meekly. In other words, China's neighbors need not formally surrender control of the waters and features within the nine-dashed line yet -- but in the end Beijing will give no ground. I suppose making Asians an offer they can't refuse is one way of getting to yes.

Levity aside, there's little reason to doubt Xi's sincerity about the importance China affixes to "core interests": shorthand for the interests for which the nation is prepared to fight, such as Taiwan and Tibet. And it is building up the capacity to fight and win. While there are many unknowns regarding the quality of the People's Liberation Army (PLA) Navy's equipment and crews, it boasts the most potential of any Asian navy.

China's maritime project is hurtling along at breakneck velocity. The PLA Navy's first aircraft carrier has taken to the seas. Shipyards are apparently starting to fabricate a second one, while the naval leadership has evidently settled on a designfor guided-missile destroyers (DDGs), which ride shotgun with any carrier task force to defend against air, surface, and subsurface threats. The navy also has help from non-naval services. The nation's first unified coast guard debuted in July and immediately set sail to enforce Beijing's claims to islands and waters in the East and South China seas.

The major unknowns concern the quality of PLA Navy equipment and crews. First consider the hardware: You can flip openJane's Fighting Ships or visit the fine folks at the consultancy GlobalSecurity to find estimates of what various armed services plan to procure, as well as technical characteristics -- ranges, payloads, rates of fire, and so forth -- illustrating how military gear should perform. We can estimate, for example, that by 2020, China will field over 70 conventional and nuclear-powered attack submarines, along with 84 destroyers and frigates, two aircraft carriers, and an assortment of smaller but still lethal craft. But it's impossible to tell in advance how weaponry and platforms will function until put to the test of combat. (This is true even of your own hardware. Having been part of the first combat use of Tomahawk cruise missiles, I can tell you we heaved a small sigh of relief when that first volley of missiles went off as advertised.) Unable to test adversaries' equipment, foreign observers rely mostly on guesswork to foresee how enemy armaments will perform under real-world conditions and thus how great a threat they pose.

For instance, Chinese naval specialists have been touting the PLA Navy's latest DDG designs as comparable to the U.S. Navy's Aegis ships, which carry state-of-the-art systems in air and missile defense. Are they? This possibility spooks U.S. maritime strategists. China's naval ambitions remain largely confined to the China seas and Western Pacific, within reach not just of the fleet but of an array of land-based weapons. Used with submarines, missile-armed patrol craft, shore-based tactical aircraft, and anti-ship missiles, an Aegis-equivalent warship would establish a serious Chinese deterrent capability in East Asian waters.

Aegis is a combined radar, computer, and fire-control system that has been around for 30 years, ever since USS Ticonderoga, the U.S. Navy's first Aegis cruiser, put to sea. But since then the U.S. Navy has made constant improvements to the system. It's entirely plausible that Chinese DDGs -- most notably the Type 052D DDG unveiled in 2012 -- are equivalent to some generation of Aegis. But is the Type 052D a 1980s, 1990s, or more recent Aegis vintage? If it's a Ticonderoga equivalent, it poses only modest cause for concern. If Chinese weaponeers have managed to leap to near parity, however, the new DDG represents an ominous development indeed.

Until the PLA Navy starts operating at sea more and using its hardware under realistic conditions, it will be tough for outsiders to glimpse inside these black boxes. This is true not just of DDGs but of stealth fighters, anti-ship ballistic missiles, and myriad other PLA systems that appear impressive but remain mostly untried. Many unknowns linger.

The human factor is another difficult variable to track. Strategic competition and war are human endeavors. The finest ship, airplane, or missile is no better than its user. How mariners perform amid the stresses of battle decides the outcomes of struggles on the high seas, but to excel in battle demands constant training and practice in peacetime. Sailors need to go to sea, a lot, to hone their skills. Yet PLA Navy operations are sporadic compared with the hectic deployment schedules customary for U.S. seafarers. Long intervals in port interrupted by the occasional short cruise provide too little experience to make seamanship, tactics, and technical proficiency second nature. Performance suffers. It's especially tough to maintain a fighting edge when one considers how seldom full-blown naval engagements take place. The U.S. Navy last battled a peer navy in 1944, when it fought Japan at Leyte Gulf. The PLA Navy has never taken on a great-power opponent.

Presently, there's reason to question the PLA Navy's battle-worthiness. If the PLA Navy operates at a higher tempo over the next decade, keeping task forces at sea for weeks or months at a time, it will evolve into a formidable force. Prospective adversaries can judge how formidable by monitoring its performance during exercises and routine at-sea operations, much as Western forces kept watch on the Soviet Navy in its heyday. Navies encounter each other at sea by chance during routine operations. Such encounters afford the opportunity to take a prospective adversary's measure, examining everything from whether its ships' hulls are rusty -- a sure sign of a poorly maintained ship and an apathetic crew -- to how smartly the officers handle their vessels on the high seas. If the PLA Navy participates in the 2014 U.S.-led RIMPAC (Rim of the Pacific) exercise, this will furnish another such opportunity. Bean-counting, then, is easy. Measuring combat effectiveness is a task of a higher, more subjective order.

But there's another, hidden variable at play. Whereas U.S. sea power is the domain of the U.S. Navy, Marine Corps, and Coast Guard, Beijing thinks about its maritime power more holistically. It's not just the PLA Navy and coast guard, but merchant shipping and even the country's massive fishing fleet. And the Chinese military backs up that fleet with shore-based implements of sea power, including anti-ship ballistic missiles furnished by the army's Second Artillery Corps and tactical aircraft from the PLA Air Force. It may appear whimsical to depict a fishing trawler as a threat to a warship bristling with guns and missiles, but fishermen can gather intelligence on foreign navies. Any U.S. Navy mariner of Cold War vintage will tell you about the Soviet AGIs, or trawlers packed with high-tech electronic sensors, that used to lurk off American seaports. When a U.S. task force emerged, the AGI would dutifully follow along, monitoring the force's movements, recording its electronic emissions, and gleaning all the data it could. Fishing fleets can also lay and clear sea mines, one of the most elusive menaces to modern navies. These are useful craft around the margins.

This all-encompassing concept of sea power lets Beijing dial up or down the degree of force it brings to bear at sea, as circumstances and competitors' actions dictate. Nor is this approach new or radical. Maoist China considered the PLA Navy a force for waging "people's war at sea," a coastal defense force meant to make things tough on powerful adversaries should they approach China's coasts. For a weak China obsessed with protecting its land, it only made sense to use every seagoing asset available to mount a seaward defense. Communist China, like imperial China before it, regards the fishing fleet and the global shipping fleet as an irregular naval auxiliary. Fishermen in particular are a sort of seagoing militia. For instance, Beijing touted their contribution to victory over South Vietnam's Navy during a 1974 clash in the Paracel Islands. This way of thinking about maritime defense persists even as the PLA Navy matures into a world-class force.

Case in point: Chinese fishing boats represented the vanguard of Chinese sea power at Scarborough Shoal in 2012, when China took possession of an atoll deep within the Philippine exclusive economic zone. Chinese fishermen were first on scene. Only when a Philippine Navy frigate tried to arrest them for poaching did Beijing dispatch unarmed or lightly armed maritime-enforcement vessels -- the forerunners to today's coast guard -- to deter further Philippine action. A protracted standoff ensued, but ultimately the Philippine contingent withdrew -- leaving Scarborough Shoal in Chinese hands. Chinese hulls -- civilian, coast guard, and navy -- reportedly encase the atoll like a "cabbage," daring Manila to try to retake it.

That's textbook Chinese maritime strategy: minimal force, deployed by naval or nonnaval platforms as the situation and the naval balance warrant. China has stayed true to its Maoist traditions. It has kept its inventory of small craft strong and numerous, furthering both commercial and military purposes, even as it fills out the upper end of an oceangoing fleet with glitzy platforms like aircraft carriers and new destroyers. This continuum -- spanning from lowly fishing boats and patrol craft able to face off against weak Asian navies (like the Philippine Navy) to blue-water combatants able to duel peer navies (like the Japan Maritime Self-Defense Force) on an equal footing -- is deeply embedded in China's maritime culture. While an economic downturn could slow down acquisitions, Beijing's basic approach will last as far into the future as the mariner's eye can see.

The PLA Navy, backed by the Chinese coast guard, shore-based air and missile forces, and unconventional auxiliaries from the commercial sector, can already make it tough and expensive for a peer navy to operate in China's geographical backyard. This is a force that could induce rivals to think twice before bucking China's will, and it outclasses lesser Asian navies by a wide margin. But will the Chinese navy venture outside Asia in force, mounting a standing presence in faraway theaters? Doubtful. Asserting control of China's environs is job No. 1. If Beijing's naval buildup continues along its current trajectory, the resulting force may let the nation put steel behind the many commitments it has taken on in the China seas, from the confrontation with Japan over the Senkaku/Diaoyu Islands to the north through the Malacca Strait to the south.

A successful naval buildup might leave ships to spare for a modest forward presence in the next-most-important theater: the Indian Ocean, the shipping lane for Persian Gulf energy supplies. Beijing sees no pressing need to venture beyond East and South Asia. So you're not about to see Chinese frigates patrolling the Mediterranean or Atlantic. Chinese leaders evince little appetite to help police an international system they deem unfair and irrational -- an artifact of Western dominance that China must amend over time. What Chinese want, and what Xi has said China will get, lies in Asia. From fighting ships to fishing boats, Beijing increasingly has the sea power to get it.