Closing the Taiwan Strait Deterrence Gap

Lessons from Air University wargaming

Jared M. McKinney is an assistant professor at Air War College. Reiss Oltman contributed to this project as an Air University fellow in the Department of Joint Warfighting, Air Command and Staff College, and John Conception contributed while a student at Air Command and Staff College.

Opinions, conclusions, and recommendations expressed or implied within are solely those of the authors and do not necessarily represent the views of the Air University, the United States Air Force, the Department of Defense, or any other government agency.

The 1979 Taiwan Relations Act includes a US commitment to make available to Taiwan the weapons necessary “to maintain a sufficient self-defense capability.” Given the increasingly asymmetric balance of power in the Taiwan Strait and the widening deterrence gap, is such an end state even possible anymore?

Initial answers are not encouraging. The most rigorous and prominent wargame, CSIS’s First Battle of the Next War, assessed that, without US military intervention, the People’s Liberation Army succeeded in destroying Taiwan’s armed forces and occupying Taipei, and that “outcome was never in doubt.”¹

To see if this result could be replicated, and to study whether different force structures could produce different — and more favorable — outcomes, Air University’s Taiwan Deterrence Warfighting Advantage Research group undertook an extensive series of wargames in 2023 and 2024 focused on an all-out PRC invasion of Taiwan with some (albeit not extensive) third-party intervention. The methods, assumptions, and scenarios used in these games are detailed in a new volume from Air University Press, Closing the Deterrence Gap in the Taiwan Strait.

Our wargames found that the CSIS baseline “Taiwan Alone” scenario was correct in its general finding — a PRC invasion could potentially succeed at significant cost. But our wargames also found that a modestly upgraded and redesigned Taiwan Joint Force could stop an invasion cold, destroying up to 75% of all PLA amphibious assets in some iterations.

A well-designed program for Taiwan’s force modernization has the potential to close the deterrence gap in the Taiwan Strait. This finding contradicts the common assertion among American and Taiwanese foreign-policy thinkers that there “is simply no realistic hope that Taiwan can hold out for long against China without America committing directly to the fight.”

This summer, we witnessed one of the largest Han Kuang military exercises 漢光演習 to date. These exercises are designed to improve Taiwan’s military readiness for a potential conflict with the PRC. This year’s drill showcased the beginnings of a shift from Taiwan’s traditional defense to a more asymmetrical approach. While this shift has been theoretically embraced in Taiwan’s new Quadrennial Defense Review, actual change has been slow, and Taiwan’s military force design has not yet been matched to the shift in strategy:

• Taiwan’s indigenous submarine program — which intends to build eight submarines over the next decade, for around US$1 billion per copy — exemplifies traditional force design over more asymmetrical approaches. The primary justification for the submarine program is that military elites in Taiwan have not publicly proposed credible alternatives.

• The Taiwan Navy canceled its previous program to build many small attack boats, instead opting to build large amphibious assault ships and next-gen frigates.

• The Taiwan Air Force has long expressed interest in the F-35B, but apparently nothing has come of that; the Air Force is also focusing on integrating MQ-9 drones, which have not performed well in less competitive environments. 

• The Taiwan Army is taking deliveries of Abrams tanks, notwithstanding questions about their suitability for Taiwan’s environment.

• After Trump’s 2024 election, early discussions in Taiwan emphasized symbolic new conventional systems — with the original reports mentioning “10 Ticonderoga cruisers and Perry frigates, 60 F-35s, 4 E-2D Hawkeye aircraft, and 400 Patriot interceptors, for a total of some $15 billion” — without articulating a clear strategic logic.

The winds may now be shifting: Taiwan’s supplemental defense budget, which is apparently in the works, may decisively shift defense investment to a truly asymmetric approach. And our Fortress Taiwan wargames demonstrate that this asymmetric-investment approach can have outsized impacts on the battlefield.

The final day of Han Kuang 41 wargames, on the island of Dongyin 東引, near Matsu 馬祖 | CNA, Dongyin Area Command photo

Below is the force design that fared the best in our Fortress Taiwan wargames:

Proposed Military Enhancements for Taiwan by 2030

• 7 squadrons of XQ-58 (1 squadron ≈ 18 drones)

  • Unit cost (US$): $6 million

  • Total cost (US$): $756 million

• 20 squadrons of NCSIST Chien Hsiang 劍翔無人機 (1 squadron ≈ 20 drones)

  • Unit cost: $6.35 million

  • Total cost: $2.54 billion

• Air-defense systems and interceptors (NASAMS, SKY BOW-III, PATROIT, etc.)

  • Total cost: $7 billion

• 30 Kuang Hua VI-class missile boats 光華六號飛彈快艇

  • Unit cost: $12.3 million

  • Total cost: $369 million

• 300 “Sea Baby” USVs

  • Unit cost: $221,000

  • Total cost: $66.3 million

• 400 “Jet Ski” USVs

  • Unit cost: $250,000

  • Total cost: $100 million

• 200 UUVs

  • Unit cost: $500,000

  • Total cost: $100 million

• 200 Hsiung Feng-III missiles 雄風三型

  • Unit cost: $2.4 million

  • Total missile cost: $480 million

  • + 3 batteries of launchers, command vehicles, and radars

    • Unit cost: ~$100 million

    • Total battery cost: ~$300 million

  • Total cost: $780 million

• 200 Hsiung Feng-IIE missiles 雄風二E巡弋飛彈

  • Unit cost: $3.1 million

  • Total missile cost: $620 million

  • + 3 batteries of launchers, command vehicles, and radars

    • Unit cost: ~$106 million

    • Total battery cost: ~$318 million

  • Total cost: $938 million

• Enhance space and cyber capabilities

  • Total cost: ~$2 billion

GRAND TOTAL: ~$14.6 billion

The main effort of the PLA’s plan for an invasion depends on a Joint Fires Campaign and the Joint Island Landing Campaign.

• The Joint Fires Campaign would aim to destroy, disable, or degrade Taiwan’s national and theater command centers, communications systems, airfields, logistics centers, and high-value defensive assets (eg. anything that could sink a ship).

• The Joint Island Landing Campaign would then seek to follow up these strikes with a massive amphibious intended to establish a lodgment on Taiwan, enabling a later breakout and advance toward political and military objectives. PLA airpower would seek to enable and protect this operation, as well as deliver “three-dimensional” threats across the island. 

The force design proposed above is centered on mitigating the Joint Fires Campaign and defeating the Joint Island Landing Campaign.

The Joint Fires Campaign promises to deliver the most concentrated firepower in modern history. Two strategies can help combat that: asymmetric airpower and air denial. The XQ-58, a Group 5 UAV that is rocket-launched and parachute-landed, could provide the Taiwan Air Force with asymmetric airpower more survivable than the current fleet of combat aircraft. Its combination of low cost, runway independence, and low observable features enables fielding in mass, as well as force dispersion during China’s Joint Fires Campaign. If successful, this would enable Taiwan to maintain asymmetric air power throughout the conflict and to continue to contest China’s bid for air dominance.

Modern air defense is expensive, but the lack of air defense is more expensive. Air denial is a bare necessity in modern warfare. Advanced layered air-defense batteries are resource-intensive, but the additional capacity they provide to degrade and survive China’s Joint Fires Campaign is critical. These materiel solutions — such as NASAMS, PATRIOT, and SKY BOW — are part of a counterstrategy that seeks to blunt the intended effects of the Joint Fires Campaign. Additional batteries of advanced air-defense systems will allow for attrition and increase the depth of Taiwan’s magazine, thus prolonging the time needed to resupply and countering more Chinese threats over time. So long as Taiwan can deny air dominance to the PLA Air Force, one of the key enablers for a successful invasion will be hampered.

The Joint Island Landing Campaign is the most critical part of the PLA’s plan for the invasion of Taiwan, so the weight of resources to counter this campaign is appropriate. These proposed material solutions come from lessons learned in Ukraine as well as best practices across our yearlong wargaming project. China fields the largest navy in the world and will be operating relatively close to its home. This necessitates the need for multiple different weapons systems across all domains to create a problem set so difficult that no military would be able to solve without high attrition rates:

• The Chien Hsiang is an indigenous radar-killing Unmanned Aerial Vehicle, like the Israeli Aerospace Industries (IAI) Harpy. This system has already been fielded, but only in small numbers; additional systems would allow for multiple attack waves that could saturate the air picture and degrade the radar systems of the invasion fleet’s defending surface combatants.

• The Kuang Hua is an indigenous missile boat smaller than many ocean-going fishing boats that carries four anti-ship missiles. Taiwan already possesses 30 of these ships but stopped building them in favor of larger warships. Adding additional missile boats allows Taiwan’s Navy to take advantage of their small size, low cost, and deadly missiles, providing a mobile firepower system that has the flexibility to defend any part of the island from multiple axes of attack.

• The “Sea Baby” Unmanned Surface Vessel — also known as the “boat drone” — has already seen its combat debut in the Russia-Ukraine War, to significant effect. Taiwan has begun developing like systems, but these proven capabilities are needed now and in mass as part of the larger counter–Joint Island Landing Campaign strategy.

• Additionally, Taiwan could develop and field the “Jet Ski Type” Unmanned Surface Vessel (also employed by Ukraine) to create a lower-cost offensive system that, while less capable than the “Sea Baby,” achieves greater mass that can increase the complexity of a drone boat attack.

• One-way attack Underwater Unmanned Vehicles pose an even greater challenge to defend against, as China’s antisubmarine warfare has been lacking for some years. These UUV systems have been under development in Taiwan for some time; Taiwan could fast-track mass production to exploit China’s weakness in this domain.

• Finally, Hsiung Feng missile systems — both subsonic (HF-IIE) and supersonic (HF-III) varieties — have extended ranges that can challenge an invasion fleet even in port. Taiwan fields these missile systems, but its current inventory is limited. Scaling these inventories would enable Taiwan to account for attrition from Chinese strikes while maintaining sufficient missiles to launch multiple waves of counterattacks.

Putting this all together, the People’s Liberation Army would have to defend against swarms of hundreds of drones in the air, surface, and subsurface, while simultaneously defending against subsonic and supersonic missile attacks. No fleet in history has seen a defensive challenge of that complexity and scale. With this proposed inventory of weapons, Taiwan could conduct such attacks on multiple waves of incoming amphibious landing operations, preventing China from effectively establishing, resupplying, and holding a long-term foothold on the Island. The operations in the Red Sea offer a glimpse of this reality, but Taiwan should be able to scale those attacks by orders of magnitude.

As we were conducting our wargames in 2023 and 2024, we grappled with the likely objection from Taiwan strategists that $14.6 billion would look like an insurmountable, unrealistic investment. Our counterargument at the time was that, if $14.6 billion was considered a bridge too far, then Taiwan’s strategists would have to contemplate the logic of opportunity cost. For instance, if the $9 billion in expected costs for submarine acquisitions were canceled, the proposals above would cost only $6 billion more than current spending allocations. Spread over a few years, this would absolutely be feasible, given the size of Taiwan’s economy.

Last month, however, Taiwanese media began reporting that Taiwan’s Ministry of National Defense will submit a supplemental defense bill to the Legislative Yuan for consideration in the winter legislative session. The proposal, reportedly in the realm of US$20 billion, appears to be relentlessly focused on the sort of asymmetric capabilities recommended by the Fortress Taiwan wargames — with drones, missiles, unmanned vessels, NASAMS, and even vertical take-off drones all under discussion.

To be sure, given the bitterness and polarization of Taiwan’s politics — emblematized by the recent failed legislative recall campaigns — it wouldn’t be surprising if the Legislative Yuan met these new proposals with skepticism.

To build a political consensus for spending more on defense, Taiwan’s politicians need to articulate how spending more will procure more security. The truth is that even massive spending on conventional military systems will not make Taiwan any more secure.

But building a force that could survive the Joint Fires Campaign and sink most of China’s high-value amphibious assets? That absolutely would. Our wargaming suggests doing so is feasible, and the successful passage and implementation of the supplemental budget under discussion would be the most decisive move in that direction in modern Taiwan history.

For more from Jared, check out the show we did together last year:

1. To be sure, CSIS wargame merely ran one iteration of the “Taiwan Alone” scenario, so this outcome must be seen as provisional only. The wargame also found that Taiwan was able to sink 16% of the PLA’s amphibious ships and inflict heavy casualties during ground combat.