In the early years after 1949, Taiwan’s defense strategy was built around the idea of one day taking back the mainland from the Chinese Communist Party. Generalissimo Chiang Kai-shek had retreated to Taiwan with that goal in mind, and for him, the move was meant to be temporary. But the reality on the ground soon set in. Taiwan didn’t have the military power or the backing from the US to make retaking the mainland a reality.

So, Taiwan pivoted to a forward defense strategy. This included stationing large numbers of troops (up to 150,000) on Taiwan’s offshore islands, such as Kinmen and Matsu, which sit just a few miles from the Chinese coast. These islands became heavily fortified outposts which sought to deter or delay a Chinese invasion and signal Taiwan’s intention to hold territory close to the mainland.  

During this time, the US played a major role in Taiwan’s defense. American forces were stationed on the island, and the military relationship was underpinned by a Mutual Defense Treaty, which was signed in 1954. That support proved crucial during the two Taiwan Strait Crises in 1954 and 1958, when Taiwan and the PRC exchanged artillery fire and engaged in brinkmanship.  

Things began to change in the 1970s. President Nixon’s visit to Beijing in 1972 signaled a major shift in US-China policy. By 1979, Washington formally recognised the People’s Republic of China and ended both its official ties and Mutual Defense Treaty with Taiwan.

In 1979, Congress passed the Taiwan Relations Act. It didn’t promise direct military intervention if Taiwan was attacked, but it did commit the US to selling Taiwan the weapons it needed to defend itself. Later, in 1982, the Reagan administration quietly issued the ‘Six Assurances,’ one of which was that the US would not set an end date for arms sales to Taiwan.

With its international space shrinking, Taiwan began focusing on self-reliance. It ramped up domestic weapons production and modernised its military. It focused on a strategy of ‘defense-in-depth,’ which involved: stopping the enemy at its shore, striking it while in transit, and destroying the enemy at the beachhead. The goal was to make an invasion so costly that Beijing would think twice, or to at least hold out long enough for potential US support to arrive.

In the early 1990s, Taiwan made a peaceful transition to democracy, and its relations with Beijing entered a new phase. Taiwan’s KMT leadership officially dropped claims to territory controlled by the CCP, and both sides tentatively agreed there was “one China”, though they interpreted that concept differently.

But tensions reignited in 1995 during the Third Taiwan Strait Crisis. Beijing, alarmed by perceived moves away from the One-China policy, fired ballistic missiles near Taiwan. Although the US responded by sending two carrier groups to the region, the crisis exposed serious gaps in Taiwan’s defence-in-depth strategy, especially its vulnerability to missile threats.  

2005: China passes the Anti-Secession Law

2016: Tsai Ing-wen elected; PRC halts cross-strait dialogue.

When the Democratic Progressive Party (DPP) came to power in 2000, Taiwan's military was already shrinking, and defense spending had dropped below 3% of GDP. At the same time, cross-strait relations between Taiwan and China were getting rockier.

President Chen Shui-bian introduced an ‘Active Defense’ strategy that focused on hitting PLA forces before they could reach Taiwan. The military invested in long-range precision weapons capable of striking deep inside China. In response, China passed the 2005 Anti-Secession Law, asserting its right to use “non-peaceful means” to bring Taiwan under its control.

When the Kuomintang returned to power in 2008, President Ma Ying-jeou took a different approach. He favored reducing tensions and adopted the ‘Hard ROC’ (Resilient Operations Concept) strategy. This focused on making Taiwan’s military more mobile, dispersed, and survivable. Ready to ride out a surprise attack and deny the PLA a quick victory. The approach aligned with the KMT's more conciliatory cross-Strait policy and recognised the diplomatic and strategic risks of launching pre-emptive actions.

A key shift of Hard ROC was moving toward an all-volunteer, professional military force. During Taiwan’s martial law era, the military had around 600,000 troops. By 2016, that number had fallen to just 215,000, and defense spending had dropped to 1.8% of GDP. All while the PLA threat was growing larger and more capable.

President Tsai Ing-wen of the DPP was elected in 2016, and Taiwan’s defense strategy went through another big shift. With China growing more assertive under Xi Jinping, Taiwan embraced a new approach known as the Overall Defense Concept, developed by Admiral Lee Hsi-ming. Rather than relying on conventional forces and more traditional defense strategies the focus under Tsia moved toward a more flexible, asymmetric force, aimed at deterring and, if necessary, withstanding a potential invasion.

Under Tsai’s leadership, the defense budget steadily increased, reaching 2.5% of GDP by 2024. She pushed to strengthen Taiwan’s self-reliance by investing in the domestic defense industry, extending mandatory military service from four months to a full year, and revamping the reserve force to make it more effective and responsive.

Understanding that modern conflicts go beyond just the military, Tsai also put an emphasis on civil defense. Her government supported training programs to help civilians prepare for emergencies, reinforcing the idea that Taiwan’s defence is a whole-of-society effort. Finally, Tsai worked to deepen ties with the United States, stepping up strategic dialogue and engaging in quiet cooperation and training with US forces to further strengthen Taiwan’s deterrence posture.

Since taking office in May 2024, President Lai Ching-te has built on the foundations laid by his predecessor in the face of escalating military pressure from China. Lai has pledged to raise Taiwan's defense budget to over 3% of its GDP, continued the shift towards asymmetric defence and emphasised the importance of societal resilience.