CHINA'S INVESTMENTS in military technology designed to keep great power militaries out of its maritime periphery are viewed with increasing concern by the U.S. foreign policy community. As these investments mature into a Chinese "anti–access/area denial" (A2AD) capability, one of the most pressing questions being asked is: how can the United States maintain its freedom of action in the Western Pacific while minimizing the risk of escalation with China? Though two competing views have emerged in this debate, both positions agree on one thing: exploiting U.S. control of the commons through a blockade of Chinese merchant shipping would be central to any strategy. For advocates of one option, known as the "AirSea Battle Concept", a distant blockade would be coupled with an offensive campaign to neutralize Chinese A2AD.¹On the other hand, proponents of the alternative "offshore control" option argue that a blockade could be used to choke Chinese commerce beyond the range of the A2AD threat.²

Despite the contribution of a blockade to either U.S. strategy, little work has been done to evaluate the feasibility of such a campaign. Indeed, existing analyses of blockade options caution that the campaign would only be useful under very limited circumstances,³ if ever,⁴ as it is too disruptive to third party shipping, too reliant on allies, too ineffectual, or too escalatory. My research examines the viability of a U.S. blockade of Chinese shipping in a limited future conflict in Northeast Asia, for example on the Korean Peninsula. But, taking into account the criticism of the blockade option in existing analysis, I consider a scenario in which all Southeast Asian countries choose to remain neutral and the United States minimizes the disruption to third party shipping. I then ask a straightforward, but critical question: in such circumstances, does the United States currently have the capabilities to implement an effective blockade for long enough to hurt China?

Although it would be a stretch, I find that United States could execute such a finely calibrated blockade. The United States could blockade the Malacca Strait and the three other alternative straits used by China to move between the Indian Ocean and the South China Sea. It could do so from outside of the South China Sea, with minimal disruption to third party shipping, and China would be virtually powerless to stop the blockade. Of course, the blockade option is even more viable if the U.S. is able to operate within the South China Sea, with the assistance of allies, or if it is willing to close the straits to third party shipping as well. However, if China is powerless to contest an effective, distant economic blockade, it will find other ways closer to home to press the United States to lift the blockade.

CHINESE DEPENDENCIES AND BLOCKADE OBJECTIVES

China imports a large proportion of oil, natural gas, and minerals to fuel its economy, and relied on exports for between 10 and 20% of its GDP in the past decade.⁵Chinese resource imports from the Middle East—mainly oil and gas—must pass through one of three straits to pass from the Indian Ocean to the South China Sea.⁶Taking into account Chinese daily oil consumption, domestic production and strategic reserves, but not rationing, overland suppliers, and the effect of a blockade on other essential commodity imports, the United States would need to sustain a blockade for at least a month and a half to hurt China economically.

The Malacca, Lombok, and Sunda Straits are natural shipping bottlenecks at which the U.S. Navy could deploy a blockade, along with an alternative route around the east coast of Australia. If the United States wishes to minimize disruption to third party shipping, it would need to identify commercial vessels of any flag with cargo coming in or out of China through any of the four waterways. Ideally, it would then send these ships back to where they came from, while allowing all other vessels to continue on to their destinations outside of China.

BLOCKADE PRECEDENT

Given these parameters, the question arises: has the U.S. done anything like this before? Indeed, the multilateral maritime interception operations in the Persian Gulf, which enforced sanctions on Iraq from 1990 until 2003, provide some critical insights into the feasibility of this type of blockade. During the first seven months of those operations, multilateral forces questioned nearly 8000 vessels for items prohibited by UN sanctions (nearly a quarter of all the vessels passing through the straits). Each day, the UN coalition conducted on average 36 queries or boarded and searched five merchant vessels, and occasionally diverted a vessel that was carrying contraband and refused to return to its origin. Special forces teams conducted 11 "takedowns" of vessels that resisted boarding.⁷

Based on these metrics, the United States would need 20 surface ships to query a quarter of the Malacca Strait's daily traffic of just over 200 ships, and an additional nine surface ships to cover the other straits.⁸ In addition, the United States would need to deploy the following capabilities at each of the four straits: an aircraft carrier to provide air support for the blockade, an attack submarine to protect the surface forces from hostile submarines, special forces teams for takedowns, and supply ships and oilers to sustain the operation. P–8 maritime patrol aircraft, essential for querying vessels in the Persian Gulf, could cover the airspace over the straits from airfields in northern Australia, with tanker support.

The Southeast Asian blockade would, however, differ from the Iraqi campaign in important ways. In some respects, the process of querying merchant ships should be simpler and more efficient. U.S. forces would only need to identify and turn away ships with cargo bound for or coming from China, without conducting the time–consuming searches for hidden contraband required for the Iraqi campaign. Commercial shipping may also decline dramatically due to the primary conflict in northeast Asia. On the other hand, the Chinese–owned merchant fleet is much larger than the Iraqi fleet.⁹ China should be expected to use creative means such as small vessels or third party vessels to circumvent the blockade, making the interceptions more complicated and less effective. Diverting a recalcitrant vessel to a friendly port, which could be as far away as Australia, could take over a week.

THE CHINESE RESPONSE

For the next few years, the only capabilities that China is likely to be able to deploy to the Southeast Asian straits to contest the blockade directly are its submarines. A Chinese submarine campaign to deter the United States from continuing the blockade would, at least, need to disable an aircraft carrier or a handful of surface warships, depending on what is at stake in the conflict. China's prospects in such a campaign would depend on the readiness, quality and quantity of its submarines, their ability to evade U.S. anti–submarine warfare (ASW) efforts, and their ability to accurately fire and evade the defenses of their U.S. targets. The People's Liberation Army Navy currently has a fleet of 61 submarines.¹⁰ Location and readiness would likely constrain the number of submarines China could dispatch to attack the blockading forces to 20. Depending on the effectiveness of U.S. ASW barriers, anywhere from two to 15 of those boats could have the opportunity to fire upon the U.S. blockading forces, although none may survive the return voyage to China.¹¹ Each boat would have the opportunity to fire at most two torpedoes or their eight anti-ship cruise missiles. U.S. forces could therefore face a substantial amount of Chinese firepower. Although their defenses may be highly effective, one successful hit with a torpedo or a handful of cruise missiles could be enough to put a carrier or destroyer out of action.¹² Moreover, if China receives some warning of the blockade fleet and U.S. forces are unwilling to fire the first shot, the Chinese submarine force could inflict significant damage on the blockade.¹³

POLICY IMPLICATIONS AND CONCLUSIONS

Taken together, my research indicates that the U.S. alone would be able to blockade Chinese merchant shipping in the Southeast Asian straits, and would effectively force Chinese submarines into a suicide mission if they wanted to contest the blockade directly. Moreover, the campaign would become even more viable if the U.S. had allied support in Southeast Asia. Diverting recalcitrant ships to a Singaporean port or flying maritime patrol aircraft out of a Philippine airfield would significantly reduce the force requirements and time taken for the U.S. to implement a blockade. In other words, an American–led blockade is a militarily feasible and effective means of pressuring China economically, while staying beyond the reach of both its A2AD and naval forces.

However, this analysis necessarily focuses on the military element of a confrontation, and says little about the political choices that such a blockade might induce in China. As Thomas Schelling noted, a blockade is a particularly effective form of coercion as it forces one's adversary to make the decision to escalate.¹⁴ But if China is both unable to contest the blockading forces and unwilling to capitulate to U.S. demands, it may instead attack those U.S. or allied targets that are within range of its conventional missiles, aircraft or naval assets. Thus, despite the military feasibility of a blockade, policymakers and analysts would need to be equally careful in designing the diplomatic demands attached to it.

REFERENCES

1 Jan Van Tol et al, "AirSea Battle: A Point–of–Departure Operational Concept," Center for Strategic and Budgetary Assessments, May 18, 2010.

2 See T X Hammes, 'Offshore Control: A Proposed Strategy for an Unlikely Conflict,' INSS Strategic Forum No. 278, June 2012; Douglas C Peifer, "China, the German Analogy, and the New AirSea Operational Concept," Orbis, Vol. 55, Issue 1 (Winter 2011), pp. 114–131. 

3 See Sean Mirski, "Stranglehold: The Context, Conduct and Consequences of an American Naval Blockade of China," The Journal of Strategic Studies (2013) Vol. 36, No. 3, pp. 385–421.

4 Gabriel B Collins and William S Murray, "No Oil for the Lamps of China?" Naval War College Review, Vol. 61, No. 2 (Spring 2008) pp. 79–95.

5 Elizabeth C Economy and Michael Levi, By All Means Necessary: How China's Resource Quest is Changing the World (Oxford University Press, 2014) p. 23, 33.

6 In 2013, 86% of Chinese crude imports passed through these three straits (see U.S. Office of the Secretary of Defense, Military and Security Developments Involving the People's Republic of China: Annual Report to Congress (2013), p.80.)

7 "Conduct of the Persian Gulf War," Final Report to Congress, April 1992, p. 101.

8 Daily shipping data is drawn from Centre for the Straits of Malacca, "Frequently Asked Questions," Maritime Institute of Malaysia, Mohd Hazmi bin Mohd Rusli, "Maritime Highways of Southeast Asia: Alternative Straits?" RSIS Commentary No. 024/2012 (2012) http://www.rsis.edu.sg/wp-content/uploads/2014/07/CO12024.pdf.

9 In 2010 China had 3209 merchant ships, while Iraq had only 40 vessels in 1990.Shipping Statistics Yearbook 2010 (Institute of Shipping Economics and Logistics, 2010) p. 240.

10 International Institute of Strategic Studies (IISS), Military Balance 2013(Routledge, 2013) p. 289.

11 The figure of 15 assumes that the ASW barriers are only 10% effective in tracking Chinese submarines, while the figure of two assumes that those barriers are 50% effective. 10% effectiveness is a conservative Cold War estimate, which is extremely conservative given the advances in U.S. ASW technology since the Cold War, while Chinese submarines are not yet as quiet as Soviet submarines at the end of the Cold War. Barry R Posen, Inadvertent Escalation (Cornell University Press, 1989), p. 174. The 50% effectiveness figure is an optimistic assessment for U.S. ASW forces hunting Chinese ballistic missile submarines today, which are noisier than the Chinese submarines that would be deployed in this scenario. See Toshi Yoshihara and James R Holmes, Red Star Over the Pacific: China's Rise and the Challenge to U.S. Maritime Strategy (Naval Institute Press, 2010) p. 141.

12 Wayne P. Hughes, Fleet Tactics and Coastal Combat (2nd ed, Naval Institute Press, 2000) p. 159–60; John C Schulte, "An Analysis of the Historical Effectiveness of Anti–Ship Cruise Missiles in Littoral Warfare," Master's Thesis, Naval Postgraduate School, Monterey CA, September 1994, p. 31.

13 The effectiveness of U.S. ASW barriers depends on the speed with which detection points are manned by ships to track and destroy Chinese submarines, and whether those ships are authorized to destroy Chinese submarines when they detect them. Presumably, the United States would wait for a Chinese submarine to fire on U.S. blockading forces before authorizing ASW forces to destroy submarines on detection. If China received any strategic warning of the blockade it could surge its forces into the open ocean before the US is able to deploy the forces necessary for an ASW barrier. Even assuming that Southeast Asian states wished to remain neutral in such a campaign, U.S. surface ships are currently deployed in the region, such as the four Littoral Combat Ships in Singapore, and could not be prevented from leaving port to establish an ASW barrier at the outset of the campaign. It would otherwise take over a week to deploy sufficient capabilities for ASW purposes at each strait from Guam. It would only take two or three days for Chinese submarines traveling at top speed to exit into the Indian Ocean. Protecting U.S. forces from the first shots in a Chinese submarine counter–coercion campaign therefore hinges on the U.S. ability to keep its forces in the region, or the campaign quiet.

14 Thomas C Schelling, Arms and Influence (Yale University Press, 1966) p. 69.