Download PDF
Commander Thomas A. Krasnicki, USN, wrote this essay while attending the College of Naval Warfare (Senior) at the Naval War College. It won the Strategic Research Paper category of the 2024 Chairman of the Joint Chiefs of Staff Strategic Essay Competitions.
The January 2023 Center for Strategic and International Studies (CSIS) publication The First Battle of the Next War: Wargaming a Chinese Invasion of Taiwan is a thorough and sobering report detailing 24 hypothetical scenarios in which China takes military action to unify Taiwan with its mainland. The publication is unique in contemporary wargaming reports in that it was conducted using open-source and unclassified information and publicly released. While the fidelity of these methods can be debated, the study concludes that direct U.S. intervention in such a scenario would result in a loss of forces not seen by the American public in generations.1 As its title implies and its authors conclude, “Opening battles, even if seemingly decisive, generally do not end a conflict.”2 To this end, if the United States is embroiled in a direct military conflict with China in the future, it must have a viable strategy to deal with the prospect of protracted war.
The now-decade-long U.S. pivot to Asia has been repeatedly undermined by emerging conflicts in other parts of the world, with Russia’s invasion of Ukraine and Israel’s offensive in Gaza being the most recent to distract U.S. attention and resources. Subsequently, the United States may not be postured or prepared to fight and win a protracted war with a peer competitor such as China in the Western Pacific unless an indirect approach is used. Data for 2016 compiled in 2021 by CSIS noted that nearly 80 percent of China’s crude oil imports are seaborne, and China’s export value by sea is $874 billion, nearly all of which passes through the South China Sea and the Strait of Malacca.3 This volume of energy imports and value of exports represent a critical vulnerability for China that its enemies can exploit should a protracted conflict arise. Simply put, the simultaneous targeting of energy imports and finished goods exports would devastate China’s economy. Predictably, China has developed a significant naval capacity and capability coupled with land-based, long-range antiship cruise missiles to shore up this vulnerability and keep U.S. and allied forces at bay.
Regardless of the current character of war represented by exquisite standoff weapons systems and contactless war, a protracted conflict will ultimately be determined by the belligerent’s ability to sustain itself and protect its economy. Naval blockade, appropriately modified for the current challenges posed by China, presents U.S. Indo-Pacific Command (USINDOPACOM) with a historically proven and viable concept of operations to end a protracted war with China on terms favorable for the United States and its allies.
Historical Use of Blockades in Pursuit of Ending War
The advanced technology available in modern warfare between peer competitors such as China and the United States dominates the narrative when assessing relative advantage. However, it cannot be discounted that when this advanced technology and perceived advantage are neutralized through attrition or other technical means, classic historical concepts such as blockade and sea lines of communication (SLOC) control remain viable methods to shape the battlespace and influence behavior. Before analyzing these methods vis-à-vis a conflict with China, it is helpful to understand how blockade and SLOC control have been used to achieve war aims in the past.
The Union blockade of Confederate ports and shipping during the American Civil War (1861–1865) provides a clear example of how major naval operations conducted at the theater-strategic level can have outsize effects on ending war. Known to posterity as the Anaconda Policy, the Union exploited a critical vulnerability of the South’s specialized economy dominated by cotton export and thus incrementally strangled the Confederate economy.4 Although the naval blockade of southern ports and shipping was not solely responsible for the Union defeat of the Confederacy, its contributions cannot be overstated.5 The direct effect on Confederate revenue loss and the overall isolation of the Confederacy from external support had long-term consequences that enabled a Union victory on land when the war was protracted over several years. Without a way to export its goods and import needed materiel, the Confederate economy could not sustain its war efforts and sued for peace. A clear parallel can be drawn between the Confederate need for export revenue to finance war efforts and China’s export-driven economy that sustains the social contract between the Chinese Communist Party (CCP) and the Chinese people. CCP’s leaders may be unwilling to accept the societal instability that could result from a protracted conflict if an economic blockade is implemented.
An analysis of the Allied blockade of Germany during World War I (1914–1919) introduces several important factors relevant to the present—specifically, the role of neutrals and the need for robust diplomatic negotiations with nonbelligerents during the conflict to maximize a naval blockade’s effect. Before the United States entered the war in 1917, neutral countries bor- dering Germany imported U.S. goods and reexported them to Germany. This process undermined the utility of the blockade. But its effect was eventually severely reduced by intense diplomatic negotiations by the Allies to curb this neutral trade with the Central Powers and by the entrance of the United States into the war.6 As early as 1916, the German military and civilian populations suffered extreme shortages of commodities, such as fertilizer, meat, fats, and other “critical materials to such an extent that the efficiency of the fighting forces went downhill.”7 Germany was unable to recover from this situation, even while drawing on continental resources. And although this blockade did not end the conflict, blockades in general can be key components to victory when a war is protracted and the civilian population can no longer sustain the fighting forces. Similarly, one could ask how long 1.4 billion Chinese citizens could endure a drastic reduction in imports and basic commodities that could not be easily replaced by drawing on their national resources.
Japanese and U.S. maritime interactions during World War II (1939–1945) in the Pacific offer a final vignette that rounds out this brief historical analysis to explain why blockade and SLOC control are such salient topics for discussion when considering a conflict against China. Beyond being similarly bound geographically, a historical view of a belligerent Japan brings up the vulnerability that reliance on externally sourced com- modities presents, specifically oil. Much like Japan required access to its southern resources area and needed to protect its internal SLOCs, China today must control these same SLOCs to ensure it can import enough energy to fuel its economy and its regional ambitions. A 1947 assessment of American destruction of the Japanese economy, the United States Strategic Bombing Survey, assessed:
Had submarines concentrated more effectively in the areas where [oil] tankers were in predominant use after mid-1942, oil imports probably could have been reduced sooner and collapse of the fleet, air arm, merchant shipping and all other activities dependent upon fuel hastened . . . and the fuel shortage might have been acute at the end of 1943 rather than a year later.8
These three historical examples validate the naval blockade’s utility in pursuing ending a war, especially during a protracted conflict with nations dependent on overseas trade. Each highlights a different facet that must be considered when proposing the use of blockade to achieve war aims: economic isolation, neutral trade and diplomatic considerations, civilian deprivation, and strategic commodity vulnerability. The following section attempts to bridge the gap between history and the present to argue why these factors are applicable in today’s era of Great Power competition with China.
China’s “SLOC Anxiety”
Chinese planners and leaders are students of history. The rapid modernization and growth of the People’s Liberation Army (PLA) Navy over the last 30 years proves the CCP is acutely aware of the vulnerabilities on which its economy is built. It is critical to emphasize that “the overwhelming majority of China’s foreign trade—over 90 percent by volume and 80 percent by value,” including manufactured goods and commodities such as food and oil, is transported by sea and through strategic SLOCs.9 The Chinese assess that this overwhelming dependence on seaborne trade must be protected, as it is the bedrock of their economy and strength. Furthermore, if a peaceful rise gives way to regional hegemonic ambitions, this dependence manifests as a critical vulnerability—what retired Rear Admiral Michael McDevitt characterizes as China’s “SLOC anxiety.”10 This anxiety has given rise to China’s force structure alignment to enable what they call “offshore waters defense,” or what the United States has previously characterized as antiaccess/area-denial (A2/AD) operations. No matter what it is called, it represents China’s attempt to protect the approaches to Chinese waters (antiaccess). Should that fail, it seeks to destroy enemy forces that penetrate its defenses or those already in Chinese home waters at the start of hostilities (area denial).11 As such, the United States must develop courses of action to defeat the effect of China’s defenses while minimizing the risk to U.S. and allied forces while pursuing their operational objectives.
Blockade for the Modern Age and Threat Environment
It stands to reason that if the United States assesses China’s access and control of strategic SLOCs as a critical vulnerability, then it can indirectly exploit this vulnerability to attack China’s center of gravity. This assumption presupposes the initial premise of this article: that deterrence in all forms has failed and China has initiated open hostilities with the United States or its allies over an issue such as the forceful unification of Taiwan with the Chinese mainland. Like the historical cases referenced herein, blockade alone will not end a protracted war. It must be coupled with other instruments of national power to be successful. With the initial conditions and caveats addressed, the mechanics of implementation can now be addressed.
The combined PLA (Army, Navy, Air Force, and Rocket Force) plans to mitigate the vulnerability presented by China’s geography and reliance on trade through strategic SLOCs for its survival. The CCP is counting on this defense array to be a sufficient deterrent to foreign interference and to prevent the blockading of its critical trade in Chinese home waters and along critical SLOCs. In general, the PLA will use a variety of munitions, such as the DF-21D and DF-26 antiship ballistic missiles, to increase the risk to U.S. and allied forces to an unacceptable limit.12 In China’s deterrence theory, the United States will be unable, or unwilling, to contest sea control in the first island chain and beyond. China’s SLOCs will remain secure with the combined might of a blue-water navy and a mobile land-based rocket force.13 The United States and its allies must develop a strategy to work within and on the periphery of these threats. A combined close and distant blockade meets this challenge.
Close and distant blockades each have inherent weaknesses that the United States and its allies must navigate to succeed in the modern threat environment of the Western Pacific. Regardless of what type is ultimately implemented, Sean Mirski asserts success is most likely to occur when blockade accomplishes “two key objectives: differentiation between neutral and enemy shipping, and neutralization of enemy shipping.”14 Ignoring differentiation risks alienating neutral states that may be needed for diplomatic assistance and result in a greater strategic failure, as positive and effective relations with neutral and partner countries bordering strategic SLOCs are vital. It would be counterproductive to restrict, inhibit, or unintentionally destroy the shipping of critical regional partners and allies such as Vietnam, the Philippines, or Singapore that are geographically critical for the U.S. regional strategy. Similarly, not adequately neutralizing enemy shipping (or keeping it in port) undermines the objective of the entire operation.
In general, a close blockade provides the unambiguous ability to search and seize vessels as required based on their known destination or point of origin by operating off specific Chinese ports.15 However, a close blockade by conventional surface vessels against a peer adversary is untenable in modern times and presents an unacceptable risk to surface forces. By contrast, distant blockades may provide weapons engagement zone (WEZ) sanctuary but offer a distinct disadvantage: “Today’s cargoes of raw materials and merchandise can be sold and re-sold many times in the course of a voyage, so the ultimate ownership and destination of a ship’s cargo is often unknowable until the moment it docks.”16 In essence, while Chinese-flagged cargo ships transiting through a distant blockade could be intercepted, neutral shipping en route to destinations other than China could easily change their final discharge ports while in transit if it made financial sense to accept the risk. This problem is somewhat self-regulating, however, as higher shipping insurance rates will deter companies from transiting conflict zone waters. The recent rerouting of shipping around Africa instead of through the Suez Canal and the Red Sea due to the threat of Houthi antiship cruise and ballistic missiles is evidence of this natural course of business risk management.
The ideal solution to this problem lies in implementing the two concepts simultaneously by employing a range of enforcement mechanisms and platforms in concert with the diplomatic engagement of neutral countries straddling strategic chokepoints, such as the straits of Malacca or Hormuz, as required due to actual threat conditions. Under this framework, close and distant blockade forces would form two concentric rings. Neutralization would be accomplished with attack submarines operating within the Chinese WEZ and long-range aircraft armed with standoff weapons operating from the periphery. Differentiation would be accomplished using a range of surface vessels, aircraft, and unmanned systems that would provide nonlethal means of interdiction and lend credibility to the U.S. effort by avoiding unnecessary lethal neutralization by inner-ring forces.17 Buttressing this concept of operations would be robust diplomatic engagement with the United Nations (UN) and all neutral parties to ensure legitimacy for U.S. actions on the world stage (although no UN resolution would be anticipated due to China’s permanent position on the Security Council).
The adoption of this framework for blockade offers several advantages to the United States and its allies in pursuit of their war aims. First, by its very nature, establishing and implementing both rings of the blockade would take time, thus providing room for deescalation and negotiation or incremental escalation of hostilities depending on the Chinese reaction to preparations.18 Second, the outer ring of the blockade could be operated by surface vessels not suitable for duty within the Chinese WEZ, such as traditional surface combatants as well as the controversial littoral combat ship fleet with embarked helicopter detachments and visit, board, search, and seizure teams. Since it is unknown how many and what type of U.S. forces may be attritted during an opening battle with China, this concept provides flexibility for outer-ring differentiation duty. Third, and perhaps most consequential, this framework is tailor-made and scalable to react to evolving conditions and adapt to strategies that USINDOPACOM wishes to initiate.
Maximizing the Effects of Modern Maritime Blockade
The scale of effort to implement this operation is understandably daunting. Narrowing the scope of the blockade to an initial energy import blockade of crude oil and liquified natural gas (LNG) bound for China while continuing to neutralize export shipping from Chinese ports may simplify the differentiation process (due to the unique physical characteristics of crude and LNG tankers) while still accomplishing the operational and strategic objectives. This specific targeting of shipping would not happen in a vacuum. Probable Chinese reactions and consequences would have to be managed. For example, China would likely reroute shipping around the Malacca Strait to alternative routes. The United States and its allies would need to be agile enough and have the capacity to control alternative trade routes, such as the Lombok and Sunda straits and the routes around Australia.19 As China’s economy slows, its oil demand will naturally decrease. For this reason, T.X. Hammes postulates that energy interdiction alone would not be enough to end the conflict; it must be coupled with neutralizing (or blockading in port) China’s export shipping.20
In theory, reducing energy imports to fuel the Chinese economy and blocking exports to market would cause instability between the Chinese population and PRC leadership. Much like the Confederacy, World War I Germany, and World War II Japan, actions taken at sea could cause destabilizing societal effects ashore in a protracted conflict. Understandably, the idea of a maritime blockade on the scale proposed may sound anachronistic when set against the backdrop of the modern threat environment that underpins China’s A2/AD strategy. However, the lessons from the protracted conflicts of history may be the key to success worthy of implementation if the enemy can neutralize the technological advantages of their opponents.
Addressing Weaknesses
Several compelling counterarguments could be made against using a blockade against China. Such counterarguments highlight the complexity of the global systems involved and the ambitious scale of the proposed endeavor. Analyzing the relative merits of such counterarguments is valuable when evaluating and understanding the risk calculus of each belligerent in a potential hot conflict between two nuclear-armed world powers.
China might react to a blockade of energy imports in several ways. Logically, it would shift its imports to overland pipeline and rail routes via Russia, Kazakhstan, and Burma. Simultaneously, China would begin rationing fuels and pull from its strategic reserve as necessary. Conservatively estimated, these factors combined could conceivably allow China to withstand a maritime blockade of energy for 21 months and upward of 8 years if additional pipelines were constructed to Russia.21 Russia’s reactions to China’s participation in a hot war with the United States will be crucial. At the time of this writing in 2024, it is safe to assume that Russia will be ready and willing to supply China with as much oil as possible unless Vladimir Putin’s regime is replaced by pro-Western leadership beforehand. Gabriel Collins and William Murray’s evaluation of Russia-China relations in this regard is succinct and direct: “No blockade of China in history has succeeded without Russian acquiescence.”22 The intent of the blockade is to inflict economic damage on China and pain on the Chinese population. If China can successfully pivot and outlast the U.S. population’s commitment to the war by inflicting its own unbearable costs on the American population, military, and economy, then the blockade strategy will prove to be fundamentally flawed.
Several issues that arise from conducting a countervalue campaign against merchant shipping versus conducting a counterforce campaign against Chinese combatants provide one of the more compelling arguments against blockade. Opponents argue that the U.S. forces needed to execute a close (countervalue) blockade and those necessary to execute a counterforce campaign are not mutually exclusive.23 The United States has a finite amount of assets that can operate inside China’s WEZ, such as submarines and long-range antiship missiles. Tasking these limited assets with two distinct objectives could prove impossible to accomplish when factoring in operational tempo and attrition.24 Prioritizing one mission over the other leaves equally unappealing outcomes. Should counterforce be prioritized, China could mitigate the inner blockade, and the previously enumerated benefits of differentiation and neutralization could be minimized to the point of ineffectiveness, resulting in adverse strategic consequences for the United States. Should countervalue operations be prioritized, in a worst-case scenario, even in victory, “the United States would confront the challenge of reaching a sustainable accord with a defeated, potentially revanchist, and still militarily powerful China.”25 This scenario may result not in a protracted war but rather an unintended episodic conflict between China and the United States.26
Rebuttal
Undoubtedly, the above counterarguments present genuine potential consequences for mishandling, miscalculating, or partial commitment to a maritime blockade of China. However, the risks can and should be mitigated. Its reliance on pipelines does not thoroughly relieve China of risk to its energy imports. As fixed infrastructure, pipelines and their associated transfer nodes are susceptible to kinetic and nonkinetic disruption and destruction.27 Coupling these effects with a blockade would shorten the time necessary to have the desired effect on China’s economy. Regarding the counterforce campaign, the United States must judiciously use its limited force and leverage allies’ and partners’ forces and capabilities to the maximum extent. The diplomatic engagement necessary for protracted conflict in this region will be as critical as any ship or weapon. Successful diplomatic engagement with regional powers (including Russia, if necessary) will augment U.S. force effectiveness and reaffirm security and defense commitments to nations within the first island chain.
Finally, this operational approach is not without risk. When analyzed in the context of escalation mitigation, though, it may present the best option or, at a minimum, the least bad option to end a protracted conflict with China.28 This plan starves the Chinese economy, but it does not destroy it. Additionally, this plan minimizes the need for deep conventional strikes on the Chinese mainland and would not reasonably raise the threat of nuclear retaliation.29 While this method may invite retaliation in kind via other domains, its employment leaves room for calculated deescalation and conflict resolution via diplomatic means. Furthermore, the preemptive, overt, and credible demonstration of the U.S. ability and willingness to impose such a blockade could be an adequate deterrent to conflict in the first place.
If China calculates that a forceful unification of Taiwan with the mainland is in its best interest, the United States must be ready to respond. If the initial battle is not decisive, the United States must be prepared to conduct a protracted war to restore the rules-based international order. Maritime blockade, modified for the current and future threat, provides one operational approach to end a protracted war on favorable terms for the United States and its allies. A combination of close and distant blockades that targets vulnerabilities in China’s supply system and export-driven economy would maximize pressure on the Chinese economy without destroying its infrastructure, thus preserving its future capacity once peace is achieved. However, this approach is not without risk and depends heavily on the U.S. ability to leverage allies and partners to pursue common goals. As such, the topic warrants further research and war gaming for validation as a viable strategy. JFQ