Taiwan: how the ‘porcupine doctrine’ might help deter armed conflict with China

Chinese president Xi Jinping made a pledge earlier this year to complete the “reunification” of China (with Taiwan). Coupled with recent violations of Taiwan’s sovereign airspace by Chinese warplanes, this has prompted widespread speculation on the island’s security.

Taiwan has been preparing for possible conflict with China for a long time. It has long acknowledged that China is too powerful to engage with in a conflict on equal terms. Accordingly, Taipei’s strategy has shifted to deterrence in terms of the human and therefore political costs making war would inflict on China. This thinking was confirmed in the recently published Quadriennal Defense Review 2021.

Taipei’s defence plan is based on a strategy of asymmetric warfare – what is known as the “porcupine doctrine”. This involves tactics for “evading enemy’s strengths and exploiting their weaknesses” and a set of escalating options that acknowledge China’s proximity to Taiwanese coast. The idea, according to the defence review, is to “resist the enemy on the opposite shore, attack it at sea, destroy it in the littoral area, and annihilate it on the beachhead”.

There have been several studies and simulations that concluded that Taiwan may at least contain a Chinese military incursion into the island. In a nutshell, the Taiwan’s porcupine doctrine has three defensive layers. The outer layer is about intelligence and reconnaissance to ensure defence forces are fully prepared.

Behind this come plans for guerrilla warfare at sea with aerial support from sophisticated aircraft provided by the US. The innermost layer relies on the geography and demography of the island. The ultimate objective of this doctrine is that of surviving and assimilating an aerial offensive well enough to organise a wall of fire that will prevent the Chinese People’s Liberation Army (PLA) from successfully invading.

Looking at these layers one by one, over the years Taiwan has developed and maintained a sophisticated early-warning system, to buy time should China launch an invasion. This aims to ensure that Beijing cannot get troops and transport ships ready to cross the Taiwan Strait in a surprise offensive. As a result, China would have to begin any invasion with an offensive based on medium-range missiles and air attacks aiming to eliminate Taiwan’s radar installations, aircraft runways and missile batteries.

If it succeeds in this, China would then have to break through the second layer of Taiwan’s defence plan in order for its troops to sail safely towards the island. But as it attempts to cross the strait, China’s navy would encounter guerrilla campaign at sea – what’s known as the “war of the flea”. This would be conducted with the use of agile, missile-armed small ships, supported by helicopters and missile launchers.

But breaking through this layer will not guarantee a safe landing for the PLA on to Formosa Island. Geography and the population are the backbone of the third defensive layer. The PLA has the capability to mount a large-scale bombing campaign on the Taiwanese island, but landing on it and deploying once there is another matter entirely.

Taiwan’s short west coast, just 400km long, has only a handful of beaches suitable for landing troops on, meaning that Taipei’s military strategists would have a reasonably easy job when it comes to working out where the PLA would try to land – especially with the sophisticated reconnaissance technology it has acquired from its US ally.

This would allow the Taiwanese miltary to set up a deadly shooting gallery to prevent PLA’s amphibious forces from making their way into the island. Even once Chinese boots were on Taiwanese ground, the island’s mountainous topography and urbanised environment would give defenders an advantage when it comes to hampering the progress of an invasion.

Taiwan’s armed forces are easily mobilised. Although Taipei has a small professional army of about 165,000 personnel, they are well trained and equipped. And they are supported by up to another 3.5 million reservists, although there have recently been criticisms that it is underprepared for an invasion.

Another factor is what UK defence academic Patrick Porter calls the “ham omelette dilemma”, because to make the omelette, a pig needs to commit its life while a chicken only has to lay a few eggs. What this means is that Taiwan will see a conflict with its adversary across the strait as conflict for survival.

For China, meanwhile, the stakes aren’t as high, despite having wanted to incorporate Taiwan for pretty much its entire modern history. And there’s no knowing how facing this existential threat might spur the Taiwanese defenders on.

The defence review also recommends the development of an indigenously produced long-range strike capability, part of a continuing move towards self-reliance for Taiwan’s defence forces. But in the meantime the country has steadily built its arsenal of defensive weapons over the past two decades, most recently agreeing the purchase of the latest patriot missiles from the US in a US$620 million (£455 million) deal agreed in 2019 between Taiwanese premier Tsai Ing-wen and Donald Trump.

Taiwan’s strategy to deter a Chinese invasion by threatening to impose major political costs is also informed by what it sees as the risk-averse nature of China’s leadership and its preference for long-term planning. And, no doubt, both sides will have taken lessons from the US experience in Afghanistan, where the political costs of taking on a small but determined and mobile enemy have recently become all-too clear.

Zeno Leoni is affiliated with King's College London