Owing to the debilitating U.S.-led wars in Afghanistan and Iraq, headlines in recent years have been dominated by discussions about land forces and counterinsurgency. But with 75 percent of the earth's population living within 200 miles of the sea, the world's military future may well be dominated by naval (and air) forces operating over vast regions. And to a greater extent than the other armed services, navies exist to protect economic interests and the system in which these interests operate. Aware of how much the international economy depends on sea traffic, U.S. admirals are thinking beyond the fighting and winning of wars to responsibilities such as policing a global trading arrangement. They are also attuned to the effects that a U.S. military strike against Iran would have on maritime commerce and the price of oil. With such concerns in mind, the U.S. Navy has for decades been helping to secure vital chokepoints in the Indian Ocean, often operating from a base on the British atoll of Diego Garcia, a thousand miles south of India and close to major sea-lanes. And in October 2007, it implied that it was seeking a sustained forward presence in the Indian Ocean and the western Pacific but no longer in the Atlantic -- a momentous shift in overall U.S. maritime strategy. The document Marine Corps Vision and Strategy 2025 also concluded that the Indian Ocean and its adjacent waters will be a central theater of global conflict and competition this century. Yet as the challenges for the United States on the high seas multiply, it is unclear how much longer U.S. naval dominance will last. At the end of the Cold War, the U.S. Navy boasted about 600 warships; it is now down to 279. That number might rise to 313 in the coming years with the addition of the new "littoral combat ships," but it could also drop to the low 200s given cost overruns of 34 percent and the slow pace of shipbuilding. Although the revolution in precision-guided weapons means that existing ships pack better firepower than those of the Cold War fleet did, since a ship cannot be in two places at once, the fewer the vessels, the riskier every decision to deploy them. There comes a point at which insufficient quantity hurts quality. Meanwhile, by sometime in the next decade, China's navy will have more warships than the United States'. China is producing and acquiring submarines five times as fast as is the United States. In addition to submarines, the Chinese have wisely focused on buying naval mines, ballistic missiles that can hit moving targets at sea, and technology that blocks signals from GPS satellites, on which the U.S. Navy depends. (They also have plans to acquire at least one aircraft carrier; not having one hindered their attempts to help with the tsunami relief effort in 2004-5.) The goal of the Chinese is "sea denial," or dissuading U.S. carrier strike groups from closing in on the Asian mainland wherever and whenever Washington would like. The Chinese are also more aggressive than U.S. military planners. Whereas the prospect of ethnic warfare has scared away U.S. admirals from considering a base in Sri Lanka, which is strategically located at the confluence of the Arabian Sea and the Bay of Bengal, the Chinese are constructing a refueling station for their warships there. There is nothing illegitimate about the rise of China's navy. As the country's economic interests expand dramatically, so must China expand its military, and particularly its navy, to guard these interests. The United Kingdom did just that in the nineteenth century, and so did the United States when it emerged as a great power between the American Civil War and World War I. In 1890, the American military theorist Alfred Thayer Mahan published The Influence of Sea Power Upon History, 1660-1783, which argued that the power to protect merchant fleets had been the determining factor in world history. Both Chinese and Indian naval strategists read him avidly nowadays. China's quest for a major presence in the Indian Ocean was also evinced in 2005 by the beginning of an extensive commemoration of Zheng He, the Ming dynasty explorer and admiral who plied the seas between China and Indonesia, Sri Lanka, the Persian Gulf, and the Horn of Africa in the early decades of the fifteenth century -- a celebration that signals China's belief that these seas have always been part of its zone of influence. Just as at the end of the nineteenth century the British Royal Navy began to reduce its presence worldwide by leveraging the growing sea power of its naval allies (Japan and the United States), at the beginning of the twenty-first century, the United States is beginning an elegant decline by leveraging the growing sea power of allies such as India and Japan to balance against China. What better way to scale back than to give more responsibilities to like-minded states, especially allies that, unlike those in Europe, still cherish military power? India, for one, is more than willing to help. "India has never waited for American permission to balance [against] China," the Indian strategist C. Raja Mohan wrote in 2006, adding that India has been balancing against China since the day the Chinese invaded Tibet. Threatened by China's rise, India has expanded its naval presence from as far west as the Mozambique Channel to as far east as the South China Sea. It has been establishing naval staging posts and listening stations on the island nations of Madagascar, Mauritius, and the Seychelles, as well as military relationships with them, precisely in order to counter China's own very active military cooperation with these states. With a Chinese-Pakistani alliance taking shape, most visibly in the construction of the Gwadar port, near the Strait of Hormuz, and an Indian naval buildup on the Andaman and Nicobar Islands, near the Strait of Malacca, the Indian-Chinese rivalry is taking on the dimensions of a maritime Great Game. This is a reason for the United States to quietly encourage India to balance against China, even as the United States seeks greater cooperation with China. During the Cold War, the Pacific and Indian oceans were veritable U.S. lakes. But such hegemony will not last, and the United States must seek to replace it with a subtle balance-of-power arrangement. COALITION BUILDER SUPREME So how exactly does the United States play the role of a constructive, distant, and slowly declining hegemon and keep peace on the high seas in what Fareed Zakaria, the editor of Newsweek International, has called "the post-American world"? Several years ago, Admiral Michael Mullen, then the chief of naval operations (and now chairman of the Joint Chiefs of Staff), said the answer was a "thousand-ship navy . . . comprised of all freedom-loving nations -- standing watch over the seas, standing watch with each other." The term "thousand-ship navy" has since been dropped for sounding too domineering, but the idea behind it remains: rather than going it alone, the U.S. Navy should be a coalition builder supreme, working with any navy that agrees to patrol the seas and share information with it. Already, Combined Task Force 150 (CTF-150), a naval force based in Djibouti and comprising roughly 15 vessels from the United States, four European countries, Canada, and Pakistan, conducts antipiracy patrols around the troubled Gulf of Aden. In 2008, about a hundred ships were attacked by pirates in the region, and over 35 vessels, with billions of dollars worth of cargo, were seized. (As of the end of 2008, more than a dozen, including oil tankers, cargo vessels, and other ships, along with over 300 crew members, were still being held.) Ransom demands routinely exceed $1 million per ship, and in the recent case of one Saudi oil tanker, pirates demanded $25 million. Last fall, after the capture of a Ukrainian vessel carrying tanks and other military equipment, warships from the United States, Kenya, and Malaysia steamed toward the Gulf of Aden to assist CTF-150, followed by two Chinese warships a few weeks later. The force, which is to be beefed up and rechristened CTF-151, is likely to become a permanent fixture: piracy is the maritime ripple effect of land-based anarchy, and for as long as Somalia is in the throes of chaos, pirates operating at the behest of warlords will infest the waters far down Africa's eastern coast. The task-force model could also be applied to the Strait of Malacca and other waters surrounding the Indonesian archipelago. With help from the U.S. Navy, the navies and coast guards of Malaysia, Singapore, and Indonesia have already combined forces to reduce piracy in that area in recent years. And with the U.S. Navy functioning as both a mediator and an enforcer of standard procedures, coalitions of this kind could bring together rival countries, such as India and Pakistan or India and China, under a single umbrella: these states' governments would have no difficulty justifying to their publics participating in task forces aimed at transnational threats over which they have no disagreements. Piracy has the potential to unite rival states along the Indian Ocean coastline. Packed with states with weak governments and tottering infrastructure, the shores of the Indian Ocean make it necessary for the United States and other countries to transform their militaries. This area represents an unconventional world, a world in which the U.S. military, for one, will have to respond, expeditionary style, to a range of crises: not just piracy but also terrorist attacks, ethnic conflicts, cyclones, and floods. For even as the United States' armed forces, and particularly its navy, are in relative decline, they remain the most powerful conventional military on earth, and they will be expected to lead such emergency responses. With population growth in climatically and seismically fragile zones today placing more human beings in danger's way than at almost any other time in history, one deployment will quickly follow another. It is the variety and recurrence of these challenges that make the map of the Indian Ocean in the twenty-first century vastly different from the map of the North Atlantic in the twentieth century. The latter illustrated both a singular threat and a singular concept: the Soviet Union. And it gave the United States a simple focus: to defend Western Europe against the Red Army and keep the Soviet navy bottled up near the polar icecap. Because the threat was straightforward, and the United States' power was paramount, the U.S.-led North Atlantic Treaty Organization arguably became history's most successful alliance. One might envision a "NATO of the seas" for the Indian Ocean, composed of South Africa, Oman, Pakistan, India, Singapore, and Australia, with Pakistan and India bickering inside the alliance much as Greece and Turkey have inside NATO. But that idea fails to capture what the Indian Ocean is all about. Owing to the peripatetic movements of medieval Arab and Persian sailors and the legacies of Portuguese, Dutch, and British imperialists, the Indian Ocean forms a historical and cultural unit. Yet in strategic terms, it, like the world at large today, has no single focal point. The Gulf of Aden, the Persian Gulf, the Bay of Bengal -- all these areas are burdened by different threats with different players. Just as today NATO is a looser alliance, less singularly focused than it was during the Cold War, any coalition centered on the Indian Ocean should be adapted to the times. Given the ocean's size -- it stretches across seven time zones and almost half of the world's latitudes -- and the comparative slowness at which ships move, it would be a challenge for any one multinational navy to get to a crisis zone in time. The United States was able to lead the relief effort off the coast of Indonesia after the 2004 tsunami only because the carrier strike group the USS Abraham Lincoln happened to be in the vicinity and not in the Korean Peninsula, where it was headed. A better approach would be to rely on multiple regional and ideological alliances in different parts of the Indian Ocean. Some such efforts have already begun. The navies of Thailand, Singapore, and Indonesia have banded together to deter piracy in the Strait of Malacca; those of the United States, India, Singapore, and Australia have exercised together off India's southwestern coast -- an implicit rebuke to China's designs in the region. According to Vice Admiral John Morgan, former deputy chief of U.S. naval operations, the Indian Ocean strategic system should be like the New York City taxi system: driven by market forces and with no central dispatcher. Coalitions will naturally form in areas where shipping lanes need to be protected, much as taxis gather in the theater district before and after performances. For one Australian commodore, the model should be a network of artificial sea bases supplied by the U.S. Navy, which would allow for different permutations of alliances: frigates and destroyers from various states could "plug and play" into these sea bases as necessary and spread out from East Africa to the Indonesian archipelago. Like a microcosm of the world at large, the greater Indian Ocean region is developing into an area of both ferociously guarded sovereignty (with fast-growing economies and militaries) and astonishing interdependence (with its pipelines and land and sea routes). And for the first time since the Portuguese onslaught in the region in the early sixteenth century, the West's power there is in decline, however subtly and relatively. The Indians and the Chinese will enter into a dynamic great-power rivalry in these waters, with their shared economic interests as major trading partners locking them in an uncomfortable embrace. The United States, meanwhile, will serve as a stabilizing power in this newly complex area. Indispensability, rather than dominance, must be its goal.