Not So Fast: Insights from a 1944 War Plan Help Explain Why Invading Taiwan Is a Costly Gamble

September 8, 2022
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If you click on enough articles, watch television, or read testimony by military leaders, you might think an invasion of Taiwan is imminent. Think tank panels spring up daily discussing how Beijing is learning from Russia’s war in Ukraine. Speculation abounds with worst-case scenarios imagining Xi Jinping using the West’s distraction in Ukraine to invade Taiwan.

While wargames and focusing attention on Taiwan’s real security challenges are important, the accompanying noise can be misleading and misses the hard reality of planning amphibious operations in the era of precision strike capabilities and information warfare. Here, historical cases illuminate some of the enduring challenges associated with invading Taiwan. While analogies are never perfect, recognizing patterns by cataloguing similarities and differences across cases helps identify key planning challenges.

 

 

In 1944 U.S. military planners drafted a plan to invade Taiwan: Operation Causeway. The plan was ultimately rejected by senior leaders due to the high costs and risks relative to alternatives for advancing against Tokyo. Analyzing Causeway provides a historical baseline against which to assess the enduring challenges of joint forcible entry operations, particularly those executed from the sea. Put simply, crossing a contested sea only to fight on complex, canalizing terrain against a deliberate defense-in-depth makes amphibious assault in Taiwan a more complex operation than even the famed 1944 Operation Overlord — the D-Day landings. A mix of Taiwanese defense planning and the reality of modern battle network competition compound these challenges, making an invasion likely harder in 2022 than in 1944.

Amphibious Assault

Amphibious assaults are a subset of joint forcible entry operations. These operations “seize and hold lodgments against armed opposition.” While there are a range of other amphibious operations, joint forcible entry is strictly concerned with assault. In joint doctrine, there are five notional stages to entry operations: 1) preparation and deployment; 2) assault; 3) stabilization of the lodgment; 4) introduction of follow-on forces; and 5) termination/transition criteria. Chinese military planning condenses these activities into three phases: 1) advance; 2) assault and penetration; and 3) exploitation and consolidation. The People’s Liberation Army divides its amphibious landing capability between its army and marine corps, with the heavy amphibious warfare associated with a Taiwan scenario in the army while its marine corps serves as a flexible expeditionary response force. Furthermore, where U.S. planning differentiates between ship-to-shore and ship-to-objective maneuver, the Chinese military divides amphibious operations between coast-to-coast and vessel-to-coast, showing the centrality of the Taiwan scenario to their doctrine and planning.

Given the complexity and risk associated with conducting landing operations in a hostile, uncertain, and non-permissive environment, amphibious assaults are usually seen as unavoidable components of larger campaigns. In the spring of 1944, the Joint Chiefs of Staff debated two courses of action designed to continue their advance to Japan. General MacArthur advocated advancing in the Philippines and seizing Luzon, which formed the base of Operation Musketeer. Admiral Chester Nimitz, alongside the Joint Staff including Admiral Ernest King, General George C. Marshall, and Army Air Force Chief of Staff Henry H. Arnold, favored bypassing Luzon and seizing Taiwan, contending that it gave them closer airbases and ports to support their advance against Japan. Where MacArthur focused on the Philippines, the Joint Staff preferred Operation Causeway, which was more oriented on theater objectives. According to the plan, turning Taiwan into an advanced base would allow the United States and its partners to “(1) Bomb Japan. (2) Support further advance into China. (3) Sever Japanese sea and air communications.”

Today, Chinese leaders would likely see an amphibious operation as a desperate last resort rather than an intermediate military objective. The end state is reunification, not establishing a staging area to further pressure Japan. Instead of taking a more indirect approach involving gray-zone pressure, a blockade, and coercive pressure designed to create a war atmosphere and pressure Taipei consistent with Chinese doctrinal writing on strategic deterrence as a continuum, Xi would only gamble and attempt to seize and exploit a lodgment as prelude to occupying the entire island. Based on historic studies of counterinsurgency — which highlight the need for 25 counterinsurgents per 1,000 citizens — this occupation force would need to be almost 600,000 strong (60 percent of the current active force) after defeating the Taiwanese armed forces, whose cohesion remains untested. China could mobilize enough forces to carry out occupation duties. The challenge would likely be the military operation that sets the conditions for a prolonged occupation. A closer look at the planning considerations in Operation Causeway illustrates that the harder challenge for Beijing would be establishing and exploiting a lodgment without suffering combat loses that dwarf Russian attrition in Ukraine.

To Establish a Lodgment, You Need to Isolate the Objective

The first challenge in invading Taiwan would be shaping or “advance” operations designed to change the correlation of forces and set conditions for landing. Causeway envisioned three phases: 1) a preliminary campaign to isolate Japanese forces on the island, which included reducing Tokyo’s ability to reinforce its garrison and counterattack in the air and sea domain; 2) an amphibious assault to seize a port and establish a lodgment; and 3) follow-on operations to destroy Japanese forces and build up airfields and ports on the island for future operations. Of note, this phasing construct is consistent with current Chinese military doctrine referenced above.

During the initial phase of Operation Causeway, which planners assumed would last 27 days, assault forces would move from across the Pacific and into staging areas while over 800 aircraft operating in an area up to 600 miles away from Taiwan attacked surface combatants, airfields, and other high-value targets. These operations would pave the way for Fast Carrier Task Forces to act as a covering force supporting the amphibious assault with close air support 96 hours prior to the attack. Of note, heavy bombers and other army aircraft planned to shift to targets on Taiwan 10 days prior to the anticipated attack to reduce Japanese indications and warnings and the ability to move forces to bolster their garrison on the island. Today, these missions could leverage rocket forces and aircraft in mainland China, potentially reducing the timeline. What would not change is the requirement to isolate the objective. China would need to be prepared to target any combatant supporting Taiwan in East China Sea, Philippine Sea, and the Luzon Strait.

In Operation Causeway, naval forces supported isolating the objective. Six task groups — each with three carriers, four battleships or cruisers, and 12 destroyers — would sortie to interdict Japanese ships and aircraft. The equivalent in today’s military would be six carrier strike groups each with a supporting surface action group. Even if China opted for land-based aviation and its rocket force to reduce this covering force requirement, it would still require large concentrations of aircraft and mobile rocket launchers to isolate Taiwan and prevent other countries from intervening. Challenges with aerial refueling, airborne command and control, and even the massive logistics required to move jet fuel and munitions to support sustained sortie generation and fires missions could limit the Chinese military’s ability to provide a large enough covering force.  Furthermore, Beijing’s naval forces would be held at risk by Taiwan’s land-based anti-ship cruise missiles operating alongside its surface combatants. China can isolate Taiwan by air and sea, but the costs and risks are uncertain.

Despite China’s overwhelming advantages in long-range missiles and aircraft operating from secure mainland bases, there would still likely be air and naval battles in the littorals associated with a joint forcible entry operation. Even if Beijing wins that battle, the attrition it suffers could complicate its decision on whether to proceed with the amphibious attack, an operation that would involve incurring additional loses. For a comparison, the Battle of Okinawa, the alternative to Operation Causeway, saw 368 allied ships damaged or destroyed, including 120 amphibious landing craft. Losses to amphibious landing craft would be particularly problematic for China if Taiwan sabotaged key ports. More recently, it took little more than the sinking of a small number of Russian ships to deny the Black Sea as littoral maneuver space necessary for conducting amphibious operations.

As seen in the Causeway timeline, Beijing will confront key temporal tradeoffs between surprise and unity of effort as it moves from the advance to assault phase. Moving the air and naval resources into position required for setting conditions for a landing would produce indicators and warnings. As China shifted from destroying Taiwan’s navy and air force to supporting the landing force, it would risk revealing the location of the amphibious assault. While Chinese military doctrine calls for joint firepower strikes as well as combined information and firepower assaults — or blitz — the timing and sequencing of these operations would still have to be integrated with amphibious assault objectives and the extent to which sustained fires might give the enemy time to reposition. In other words, you can concentrate fires on the objective and reveal your intentions or risk leaving the beach landing at risk.

China has the overwhelming preponderance of force, but Taiwan’s hardened facilities, mobile radars, and asset mix would make it difficult for Chinese planners to be confident they had degraded Taiwan enough to proceed to the assault phase. More critically, China would have to make a critical decision early in the war: whether or not to strike U.S. and Japanese bases and assets in its advance phase.  Keeping the United States and Japan out of a war with Taiwan would significantly alter the balance of forces but risk counterattacks and/or counter-landing operations.

To Occupy an Island, You Need a Port

In the second phase, Operation Causeway called for simultaneously overrunning modern Kinmen Island to secure lines of communication while seizing a lodgment in the southern port of Kaoshing with a force of 402,000 soldiers and marines, compared to 98,000 Japanese defenders — a 4:1 ratio. This relative combat power ratio didn’t take into account the overwhelming allied superiority in ships and aircraft or terrain which, consistent with modern approaches, would push the ratio closer to 10:1. For a modern comparison, Taiwan has 170,000 active duty personnel and over 1 million trained reservists, coupled with advanced air defense and coastal defense capabilities and decades of building hardened fighting positions and obstacles that would complicate an amphibious assault. Even if Beijing accurately assesses relative military power, hard under any circumstance, they would still confront difficulty in assessing the population’s will to fight, a key feature of the war in Ukraine.

In analyzing Taiwan in 1944, planners concluded that the geography made it necessary to establish a lodgment on the southern tip of the island and use it as a base of operations to build up enough combat power to clear the coastal plan on the west of the island — where the majority of the population lives — from south to north. Terrain and logistics drove the selection of the landing objective. The port in Kaoshing was seen as the best candidate, given that it was near an airfield and there were northern and eastern rivers outside the city which the amphibious force could use as an initial defensive perimeter.

Image courtesy of the U.S. government

According to the plan, “the strength of total forces to be employed … is limited by the capacity” of the port. The plan envisioned sending in teams to repair and develop airfields, ports, and identifying intermediate staging areas to reconstitute forces. The staff estimated it would take over 90 days just to build up enough combat power to shift from the assault phase to what modern PLA doctrine calls exploitation and consolidation. In other words, without a working port, China would likely struggle — in the same way imagined in 1944 — to introduce enough forces to defeat the Taiwanese military in less than 90 days.

The requirement to use a port to build up combat power on the island created a critical vulnerability. According to the 1944 plan, “it is estimated that enemy action to block and damage the harbors and bridges and our offensive operations will greatly curtail the harbor and road capacities in the early stages.” While China has shorter lines of communication to project power to Taiwan than the Causeway plan envisioned, it likely still needs a port and would struggle to expand the lodgment against a determined defender. Operation Causeway planners estimated that the assault phase would result in 37,000 causalities (roughly 10 percent of the force) in less than 60 days. These casualty counts exceed even the largest estimates from Ukraine. There is also the open question of whether China’s authoritarian state and censors can hide mass casualties for an extended period of time from a digitally savvy public. China has enough combat power to overwhelm Taiwan, but the losses and operational difficulties could make it a pyrrhic victory at best.

Conclusion: The Unlikely Invasion

Ultimately, war is a continuation of politics by other means. Politicians can gamble even when confronted with difficult military plans just as military leaders can skew estimates to gain political favor. What ultimately pushed the U.S. Joint Chiefs to decide against invading Taiwan was a mix of the logistical nightmares inherent in the operation alongside General MacArthur’s efforts, which included direct outreach to political figures, to push for invading Luzon. By late summer 1944, planners decided to postpone a decision on whether or not to execute Operation Causeway based on progress in the Southern Philippines. By September 1944, they set aside the plan altogether and focused on Operation Iceberg, the invasion of Okinawa.

The sheer size, scale, and complexity involved with invading Taiwan likely checks even the most self-serving and impetuous instincts inside the Chinese Community Party. Court sycophants and hawks have viable alternatives to invading Taiwan that they can recommend as they seek to win favor and shape the future of modern China. The enduring challenges associated with terrain, logistics, and force-ratios on display in Operation Causeway have only compounded over time. Even if the plan is not a guide used by the Chinese military, it offers a reminder of the complexity of joint forcible entry operations.

Military planners are tasked with balancing the most likely and most dangerous enemy courses of action as they develop viable options for political leaders. The more democracies — and not just the United States — can help Taiwan deny littoral access and beachheads, the less likely Chinese leaders will be to pursue an amphibious landing. Furthermore, the more this assistance supports alternative coercive scenarios like countering a blockade and large-scale air incursions, the better it helps Taiwan deter by denial and buy time for new political and economic forces to walk back more aggressive tendencies in Beijing. For example, helping Taiwan build resiliency into its battle networks supporting the tracking (and targeting) of Chinese forces will help Taipei offset Beijing’s power preponderance. If the reality of integrated deterrence and JADC2 come to fruition, these local partner networks could also provide options for the United States and partner nations to plug into Taiwan’s battle network, further complicating Beijing’s calculus.

 

 

Benjamin Jensen, Ph.D., is a professor of strategic studies at the School of Advanced Warfighting and a senior fellow for future war, gaming, and strategy at the Center for Strategic and International Studies.

The views expressed are his own and do not reflect the views or positions of the U.S. Marine Corps, the Department of Defense, or any part of the U.S. government.

Image: Jack Proctor, Blue Mountains City Library