CSIS: Wargaming a Chinese invasion of Taiwan

The Center for Strategic and International Studies has issued a major report on a potential Chinese invasion of Taiwan, using a wargame specially developed for the study.

China’s leaders have become increasingly strident about unifying Taiwan with the People’s Republic
of China (PRC).1 Senior U.S. officials and civilian experts alike have expressed concern about Chinese intentions and the possibility of conflict. Although Chinese plans are unclear, a military invasion is not out of the question and would constitute China’s most dangerous solution to its “Taiwan problem”; it has therefore justly become a focus of U.S. national security discourse.

Because “a Taiwan contingency is the pacing scenario” for the U.S. military, it is critical to have a shared, rigorous, and transparent understanding of the operational dynamics of such an invasion.2 Just as such an understanding was developed concerning the Cold War’s Fulda Gap, so too must analysts consider the Taiwan invasion scenario. This understanding is important because U.S. policy would be radically different if the defense were hopeless than if successful defense were achievable. If Taiwan can defend itself from China without U.S. assistance, then there is no reason to tailor U.S. strategy

to such a contingency. At the other extreme, if no amount of U.S. assistance can save Taiwan from
a Chinese invasion, then the United States should not mount a quixotic effort to defend the island. However, if U.S. intervention can thwart an invasion under certain conditions and by relying on certain key capabilities, then U.S. policy should be shaped accordingly. In this way, China would also be more likely to be deterred from an invasion in the first place. However, such shaping of U.S. strategy requires policymakers to have a shared understanding of the problem.

Yet, there is no rigorous, open-source analysis of the operational dynamics and outcomes of an invasion despite its critical nature. Previous unclassified analyses either focus on one aspect of an invasion, are not rigorously structured, or do not focus on military operations. Classified wargames are not transparent to the public. Without a suitable analysis, public debate will remain unanchored.

Therefore, this CSIS project designed a wargame using historical data and operations research to model a Chinese amphibious invasion of Taiwan in 2026. Some rules were designed using analogies with
past military operations; for example, the Chinese amphibious lift was based on analysis of Normandy, Okinawa, and the Falklands. Other rules were based on theoretical weapons performance data, such as determining the number of ballistic missiles required to cover an airport. Most rules combined these two methods. In this way, the results of combat in the wargame were determined by analytically based rules instead of by personal judgment. The same set of rules applied to the first iteration and to the last iteration, ensuring consistency.

Based on interviews and a literature review, the project posited a “base scenario” that incorporated the most likely values for key assumptions. The project team ran that base scenario three times. A variety of excursion cases then explored the effects of varying assumptions.3 The impact of these varying assumptions on the likely outcome is depicted in a Taiwan Invasion Scorecard (see Figure 8). In all, 24 iterations of the game mapped the contours of the conflict and produced a coherent and rigorously derived picture of a major threat facing the United States.

The Results

The invasion always starts the same way: an opening bombardment destroys most of Taiwan’s navy and air force in the first hours of hostilities. Augmented by a powerful rocket force, the Chinese navy encircles Taiwan and interdicts any attempts to get ships and aircraft to the besieged island. Tens of thousands of Chinese soldiers cross the strait in a mix of military amphibious craft and civilian roll- on, roll-off ships, while air assault and airborne troops land behind the beachheads.

However, in the most likely “base scenario,” the Chinese invasion quickly founders. Despite massive Chinese bombardment, Taiwanese ground forces stream to the beachhead, where the invaders struggle to build up supplies and move inland. Meanwhile U.S. submarines, bombers, and fighter/attack aircraft, often reinforced by Japan Self-Defense Forces, rapidly cripple the Chinese amphibious fleet. China’s strikes on Japanese bases and U.S. surface ships cannot change the result: Taiwan remains autonomous.

There is one major assumption here: Taiwan must resist and not capitulate. If Taiwan surrenders before U.S. forces can be brought to bear, the rest is futile.

This defense comes at a high cost. The United States and Japan lose dozens of ships, hundreds of aircraft, and thousands of servicemembers. Such losses would damage the U.S. global position
for many years. While Taiwan’s military is unbroken, it is severely degraded and left to defend a damaged economy on an island without electricity and basic services. China also suffers heavily. Its navy is in shambles, the core of its amphibious forces is broken, and tens of thousands of soldiers are prisoners of war.

You will find the full report at the link above, including its recommendations for US,Taiwan, and allies. The launch event was livestreamed on YouTube, and can be found below. Stacie Pettyjohn (CNAS) makes a particular good point about the value of multiple organizations undertaking multiple, different games (in both the public and classified spaces) to enhance the robustness of overall findings.

For press coverage of the report, see:

• CNN
• Guardian

For other Taiwan invasion wargames, see this summary Drew Marriott published at PAXsims in December 2021.