Typical discussions of the South China Sea overstate its importance. Strategist Robert Kaplan has written that “the South China Sea is the future of conflict” and has “critical geo-strategic importance,” because it contains the world’s most important sea lanes and “potentially huge” energy resources.1 These arguments deserve skeptical reception.
Conventional wisdom holds that core U.S. national security interests include preserving the physical safety of the American people, promoting a “deep peace” in Eurasia to avoid great power war, and preventing the rise of a Eurasian hegemon.2 While U.S. military power is sufficient to balance China today, in the future, the United States might need India, Russia, and Japan to offset Chinese strength.3 Thus, the United States needs to protect the sea lanes of communication to enable India, Russia, and Japan to join a China-balancing coalition, should Chinese behavior motivate them to overcome their differences and form one.
Even if we accept this description of U.S. interests, how convincing are Kaplan’s arguments?
South China Sea Shipping Lanes
Kaplan is correct about the prominence of South China Sea sea lanes in the peacetime world economy. More than $5 trillion in goods moves through the sea every year, including “two thirds of South Korea’s energy supplies, nearly 60 percent of Japan’s and Taiwan’s energy supplies, and 80 percent of China’s crude oil imports.”4 But the sea lanes’ peacetime importance does not mean they would be economically vital in the event of war.
Tankers and container ships rely on the South China Sea in peacetime because the global shipping market is highly competitive, and firms use the most direct routes lest they lose profits and market share. But what if Chinese forces were able to deny Japan- or South Korea–bound merchantmen transit?
These ships could instead go around Indonesia or Australia and follow Pacific Ocean routes thousands of miles from Chinese naval bases.5 Such roundabout routing would sharply reduce the threat posed by Chinese ships and aircraft while increasing the Chinese warships’ risk of being found and sunk. As Chinese ships and submarines moved farther from their bases to pursue merchantmen, they would move away from land-based air cover and toward areas where U.S. and Japanese surface ships and maritime patrol aircraft could operate against them with impunity.
China still could disrupt South Korean and Japanese seaborne trade—submarines could deliver bottom mines or launch torpedoes against tankers approaching Tokyo Bay oil terminals, for example—but the United States would not need to control the South China Sea in wartime to enable Japan and South Korea to trade with major (non-Chinese) markets or to establish secure lines of communication between the members of a China-balancing great power coalition, should one form.
On the down side, roundabout routes would increase shipping costs, shipping time, and the number of merchant vessels required to maintain a given level of throughput. But for many important commodities, these costs would be minor. A roundabout route tripling the distance from the Arabian Gulf to Yokohama, for example, would increase oil shipping costs by only $6 per barrel.6
Roundabout routing also would not secure shipping lanes to ports that serve allies such as the Philippines, historical Chinese adversaries such as Vietnam, or Taiwan. The same Chinese antiaccess/area-denial capabilities that could make the northern South China Sea a contested zone also could be used to attack ships bound for Haiphong or Manila. Does that mean, as Kaplan asserts, that wartime control of the South China Sea would put China “a long way toward dominating the navigable rimland of the Eastern Hemisphere”?7
No. Overland routes would permit the United States to ship weapons and other supplies to Vietnam; myriad shipping channels for relatively small vessels would enable similar shipments to the Philippines from the east. In addition, the experience of the 1980s’ Gulf tanker war suggests that, given the prospect of lucrative trade, shippers respond to attack by charging higher rates and paying crews to bear increased risk, not by ceasing operations.
Now consider the importance of South China Sea routes for U.S. warships.
In the event of a U.S.-China war, U.S. submarines presumably could transit the South China Sea at will. China does not have first-class antisubmarine warfare (ASW) capabilities and cannot lay enough mines to render the South China Sea impassible.8 The U.S. Navy might choose to use roundabout routes to move surface ships from the Indian Ocean to the Pacific should it judge the risk of attack from land-based Chinese aircraft too high.
Thus, avoiding the South China Sea would mean a few weeks’ delay, but is that prospect enough to give the South China Sea “critical geo-strategic importance”? Again, no. Naval forces coming from the Arabian Gulf region likely would be no more than two carrier strike groups. If additional aircraft were needed in the Far East in a hurry, the United States could send far larger numbers by ferrying them to Japanese airbases.9
What About Taiwan?
Taiwan would face serious difficulties defending itself against a determined and prolonged Chinese attack, even if its South China Sea lines of communication were not threatened.
Taiwan’s defensive problems arise from two fundamental sources: Politically, its status matters far more to China than to the American people. Militarily, it lies within range of more than 1,000 Chinese short-range ballistic missiles (SRBMs), which are deployed on mobile launchers and thus are extremely hard to find and destroy.
These SRBMs could sink Taiwan Navy ASW and mine countermeasures (MCM) ships and merchantmen in port, making it difficult or impossible for other ships to come and go. They could crater runways from which the Taiwan Air Force and fixed-wing maritime patrol aircraft might otherwise be able to operate. Indeed, over time, and in conjunction with follow-on attacks by conventional aircraft, an SRBM-led bombardment might effectively ground the Taiwan Air Force, enabling Chinese aircraft to dominate the air over the Taiwan Straits. At that point, those aircraft could slow or stop Taiwan MCM and ASW efforts, reseed minefields, and attack merchantmen directly.
Given the Chinese SRBM threat, Taiwan needs to emphasize a “porcupine defense.”10 It also should stockpile critical supplies to enable it to ride out a Chinese blockade for an extended period.Such measures, which would buy time and make it harder for China to subdue Taiwan, would be required even if South China Sea sea lanes were secure.
South China Sea Energy Resources
Kaplan cites estimates of 900 trillion cubic feet (TCF) of natural gas and 7 billion barrels of oil in the South China Sea, although he also gives some credence to Chinese estimates of 130 billion barrels of oil.11 He notes Vietnamese and Filipino concerns that China might seize these energy resources at their expense, given the various ways China flouts international norms. In the past, these small states have looked to the United States to prevent China from dominating the region. Kaplan apparently believes the United States should continue to extend such help.
This line of thinking calls for scrutiny. First, substantial evidence from authoritative sources argues against the 130 billion barrel figure. In a 2013 analysis, the U.S. Energy Information Administration (EIA) estimated “proved or probable” oil reserves at 11 billion barrels. Its natural gas estimates also were smaller, at 190 TCF.12
Kaplan asserts that the territorial disputes over “small islands, rocks, and coral reefs . . . give the South China Sea critical geo-strategic importance . . . mainly because of the oil and natural gas that might lie nearby.”13 Again, this argument lacks empirical support. According to the EIA, “most fields containing discovered oil and natural gas are clustered in uncontested parts of the South China Sea.”14
EIA’s estimates suggest South China Sea reserves make up less than 1 percent of world oil reservesand a little under 3 percent of world natural gas reserves.15 Regions genuinely considered strategic because of the size of their reserves have much more. The Middle East, for example, holds 49 percent of the world’s oil reserves and 41 percent of its natural gas reserves.
If large recoverable South China Sea reserves do exist, it would be good news. The United States maintains its large and costly military in part to prevent supply disruptions in the politically volatile Middle East and thereby ensure the unimpeded flow of Arabian Gulf oil to world markets. Oil production in other parts of the world reduces the risks that supply disruptions pose to U.S. (and global) prosperity.
In addition, the United States has an interest in peaceful dispute resolution all over the world, in particular between a rising China and its smaller neighbors on the South China Sea. And disputes over oil can lead to violence. But South China Sea oil will reach world markets no matter who extracts it. In principle, resulting profits might be enjoyed by China, Vietnam, the Philippines, Malaysia, Brunei, or some combination. It is hard to see why the winners’ identities would be a matter of “critical geo-strategic importance” for the United States.
A New Sort of Adversary
The United States today confronts a great power competitor different from those of the 20th century. China is unlike Imperial Japan, whose economy and population were far smaller. It is unlike Nazi Germany, whose initial military prowess could not offset blunders that made the Soviet Union a U.S. ally. It is unlike the Soviet Union, which possessed a peer military but a sclerotic economy.
By 2040, the United States could face a nation with triple its resources to use in influencing outcomes in international relations.16 Given this prospect, the United States needs to distinguish vital interests from lesser ones. Is U.S. preeminence in the South China Sea necessary to secure core U.S. national security interests? Is the real issue regional status, and whether China or the United States gets to decide who can occupy islets, exploit resources, or conduct peacetime military operations? If status concerns are the real issue, is it worth risking war with a nuclear power to ensure China cannot exert South China Sea influence akin to what the United States historically has exerted in the Caribbean? To form sound answers to such questions, the United States might benefit from an open-minded and evidence-driven debate about the South China Sea.
Author’s Note: For helpful comments on earlier versions of this article, the author wishes to thank retired Navy Captains Thomas Fedyzsyn, Wayne Hughes, and Jan van Tol, as well as several anonymous Naval War College faculty members.
1. Robert D. Kaplan, “The South China Sea is the Future of Conflict,” Foreign Policy, 15 August 2011, and Asia’s Cauldron: the South China Sea and the End of a Stable Pacific (New York: Random House, 2014), 10.
2. Robert Art, A Grand Strategy for America (Ithaca, NY: Cornell University Press, 2003), 140. Art identified the first two interests. Aaron Friedberg asserts the third in A Contest for Supremacy: China, America, and the Struggle for Mastery in Asia (New York: W. W. Norton & Company, 2012), 254.
3. Barry Posen argues that “over the next several decades . . . a coalition of . . . Japan, Russia, and India . . . may need the United States . . . [to] . . . offset Chinese power . . . and the United States may need [them].” Barry Posen, Restraint: A New Foundation for US Grand Strategy (Ithaca, NY: Cornell University Press, 2014), 91.
4. Max Fisher, “The South China Sea: Explaining the Dispute,” The New York Times, 14 July 2016, and Kaplan, Asia’s Cauldron, 11.
5. Jan van Tol points out that “Japanese SLOCs would be rerouted further north, well away from the reach of most PLA A2/AD systems.” Jan van Tol, Mark Gunzinger, Andrew Krepenevich, and Jim Thomas, “Air Sea Battle: A Point of Departure Operational Concept,” Center for Strategic and Budgetary Assessments, 2010, 79.
6. Author’s estimate based on Energy Information Administration data.
7. Kaplan, Asia’s Cauldron, 14.
8. Were China to make dramatic improvements in its ASW capabilities, it still would be hard to find U.S. submarines in the relatively shallow waters of the northern South China Sea. For more detail, see Owen R. Cote Jr., “Assessing the Undersea Balance Between the U.S. and China,” MIT Security Studies Program Working Paper, February 2011.
9. Is the South China Sea geostrategically critical because China relies on SLOCs there? Probably not. A U.S. blockade has a chance only if all China’s land neighbors fully support U.S. efforts, despite enormous financial (and other) incentives not to do so.
10. A “porcupine defense” is one that inflicts great pain on attackers but threatens others not at all. See, for example, William Murray, “Revisiting Taiwan’s Defense Strategy,” Naval War College Review, 61, no. 3 (Summer 2008): 12−38.
11. Kaplan, Asia’s Cauldron, 10.
12. Energy Information Administration, “Contested Areas of South China Sea Likely Have Few Conventional Oil and Gas Resources,” 13 April 2013.
13. Kaplan, Asia’s Cauldron, 10.
14. Energy Information Administration, “Contested Areas.”
15. EIA, “Crude Oil Proved Reserves,”and EIA, “Proved Reserves of Natural Gas.”
16. Graham Allison, Destined for War: Can America and China Escape Thucydides’s Trap? (Boston: Houghton Mifflin Harcourt, 2017), 216.