Sea Denial, U.S. Maritime Strategy, and Conventional Deterrence of China

In the February 2014 issue of Naval Institute Proceedings, retired U.S. Navy Commander Victor Vescovo suggested that a maritime strategy relying primarily on sea denial capabilities could be sufficient to deter Chinese aggression against America’s East Asian allies. Vescovo outlined how wartime offensive minelaying in the vicinity of major Chinese ports by U.S. submarines and long-range aircraft could severely damage the export-driven Chinese economy. Vescovo appears to endorse strategies emphasizing conventional deterrence by punishment and compellence by economic coercion, both of which can be highly problematic for reasons I’ve previously addressed.

However, the latent ability to use offensive mining to bottle People’s Liberation Army Navy (PLAN) forces up in their home ports—and also cut crisis-surged units off from returning for rearmament and repair—could greatly buttress conventional deterrence by denial. This notion dovetails with a November 2013 RAND Corporation study that highlights how modern, highly mobile coastal anti-ship cruise missile batteries deployed in the Ryukyus, South Korea, Taiwan, the Philippines, Malaysia, and Indonesia could pose a severe challenge to Chinese wartime passage through the key straits that would provide them access to the Indian and Western Pacific Oceans. Both the mining and coastal missile concepts are captured within the December 2013 testimony of prominent Naval War College Chinese maritime strategy expert Andrew Erickson  to the House Armed Service Committee’s Seapower and Projection Forces subcommittee as well as his related article in The National Interest. Erickson additionally (and rightly) argues that conventional deterrence by denial can be further reinforced via latent U.S. threats of using submarines and long-range aircraft for traditional Anti-Surface Warfare (ASuW) operations within contested zones in the event of a war, or if need be to pummel Chinese expeditionary lodgings upon allied territories with land-attack missiles.

These commentators are absolutely correct that sea denial is an essential element of any U.S. strategy for deterring China—and failing that, for defending America’s East Asian allies under fire. Blunting PLAN operations in the East and South China Seas, not to mention preventing effective PLAN breakouts from the First Island Chain, would go a long way towards preventing China from attaining certain types of political objectives in an East Asian war. U.S. and allied sea denial operations would indeed make it enormously difficult for China to undertake a large-scale invasion of a sizable allied territory, persist in holding any small and isolated allied territories it seized in a hostilities-igniting gambit, use surface forces (including future aircraft carriers) to blockade or conduct land-attack strikes against allied territories, sortie submarines into the Western Pacific for ASuW or land-attack tasks, suppress opponents’ submarine operations inside the First Island Chain, or protect its flow of logistical support to its expeditionary forces.

Chinese wartime political objectives might not necessarily require that the PLAN obtain or maintain sea control in these bodies of water, though. If Chinese leaders sought to coerce a U.S. ally through a maritime blockade, and their valuation of their political objectives drove them to use lethal and not necessarily discriminate force to enforce this embargo, minelaying and traditional ASuW operations by Chinese submarines and land-based aircraft might be entirely adequate. While Chinese sea denial operations might not present a major concern for the U.S. with respect to unpopulated allied territories, they would pose a critical problem with respect to populated ones. Could the southern and central Ryukyus (especially urban Okinawa) hold out indefinitely if their flow of basic foodstuffs, petroleum products, or other staple goods were heavily disrupted? How drastically might the developing Philippine economy be affected if its major ports in western Luzon were pressured? The question’s applicability to Taiwan should be obvious.

Furthermore, any U.S. or allied forces stationed in or operating from blockaded, geographically-isolated friendly territories (the Ryukyus again come to mind) would find their logistical lifelines endangered. If the sea blockade could not be breached via airlift due to insufficient cargo aircraft capacity or perhaps Chinese offensive counterair operations, then these critical lines of communications might be severed altogether. U.S. and allied forces in ‘frontline’ territories could certainly make use of ordnance, food, and other supplies stockpiled (and concealed) near their positions during peacetime—if such foresighted steps had been taken. If not, or if the conflict became protracted, how long would they be able to sustain operational effectiveness with their maritime lines of communication under such pressure? What if the U.S. and allied plan was to surge assets such as anti-ship or anti-air missile batteries to these forward territories only upon detecting Indications and Warning of possible Chinese aggression? If warning signs were missed, or if crisis-psychological factors delayed the U.S. and allied reactions to those signs until too late, could campaign-critical defensive assets warehoused in rear areas be transported to the ‘frontline’ and then emplaced while under fire? If the answers to these questions are highly doubtful or clearly in the negative, then conventional deterrence theory makes clear that it would be unlikely such a force or its associated strategic concept would be an effective deterrent. ‘Mutually-assured’ sea denial cuts both ways.

All this also says nothing about scenarios in which the People’s Liberation Army (PLA) might employ conventionally-armed ballistic and cruise missiles to bombard allied military, economic, and civil targets as a means of coercion. U.S. and allied sea denial operations could do nothing to directly counter such a thrust. PLA suppression of U.S. forward airbases via periodic cruise missile (and perhaps short-range ballistic missile) bombardments would additionally reduce the screening air cover available to protect sea (and air) lines of communication to the embattled ally as well as support friendly forces’ own sea denial operations.

Should the Chinese combine missile bombardment with a submarine and aircraft-enforced blockade, there would be a real risk of rendering U.S. and allied forces in ‘frontline’ territories hors de combat. The PLA might not be able to physically seize or hold those territories, but if the U.S. and its allies could not break the Chinese blockade and roll back China’s ability to continue at-will bombardment, then it is entirely conceivable Chinese leaders might be satisfied by forcibly compelling the U.S. and its allies to militarily withdraw from the territories as the price of a settlement. For instance, the prime Chinese objective in a limited war with Japan and the U.S. might very well be demilitarization and eventual political Finlandization of the Ryukyus. A U.S. conventional deterrent resting purely on sea denial would not be sufficient to prevent this kind of war, and it follows that allowing the maritime approaches to U.S. allies’ populated territories to become a de facto ‘no-man’s land’ would be self-defeating.

U.S. conventional deterrence credibility therefore not only depends upon U.S. forces’ abilities to assert maritime denial against PLA operations in the combat theater, but also their abilities to obtain and exercise localized maritime control within the approaches to allied territories. Protection of these sea and air lines of communication, not to mention the associated sea and air ports of debarkation, may be possible using Joint combined arms including sea-based and theater-range land-based aircraft, naval surface and subsurface forces, land-based air and missile defenses, and defensive naval minefields.

In a major war, though, these measures alone might not be adequate for obtaining maritime control when and where needed. The PLA’s quantitative advantages in theater combined with China’s physical proximity to the probable contested zones suggest PLA forces would be able to attain higher operational tempos than their U.S. and allied counterparts. This differential would be further aggravated if China engaged in a conventional counterforce first strike. Maritime lines of communication protection might consequently depend upon taking actions that suppress PLA operational tempo and offensively attrite the PLA forces engaged in sea denial operations.

Such actions might include cyber or electronic attacks that disrupt, deceive, or exploit PLA maritime surveillance/reconnaissance systems and networks, command and control networks at the operational and tactical levels, or logistical support networks. They might also include offensive maritime operations designed to lure PLA maritime forces into battle on terms that strongly favored the U.S.; an example might be an attempt to draw PLA maritime strike aircraft into an aerial ambush with a convoy or a U.S. Navy task group approaching the First Island Chain serving as bait. In the event China did set the escalatory precedents of unleashing a conventional first strike against U.S. and allied forces and bases, the U.S. could conceivably (and with legal, moral, and operational justification) respond with conventional strikes against equivalent PLA targets on Chinese soil.

It is clear, then, that just as U.S. and allied sea denial capabilities would curtail the PLA’s ability to invade and occupy allied territories, U.S. and allied maritime control capabilities—plus the latent threats posed by U.S. long-range strike capabilities—would be necessary to prevent ‘frontline’ East Asian territories and the friendly forces defending them from withering on the vine. The region’s geography, the PLA’s ever-expanding maritime and land-attack capabilities, and the plausible spectrum of Chinese political objectives and conflict scenarios make it so. Indeed, a conventional deterrent must be designed such that it can cover this full spectrum if it is to enduringly prevent war; one that covers only a narrow range of contingencies risks catastrophic failure if it cannot match up to the unique circumstances of a crisis or the political objectives of an intelligent and determined opponent. U.S. conventional deterrence of China (and U.S. maritime strategy) accordingly must embrace sea denial, but cannot solely rely upon it.