As Japan weathers pressure from China after Prime Minister Sanae Takaichi said last month that an attack on Taiwan would constitute a ‘survival-threatening situation’, Taiwan’s own opposition parties risk undermining that support.

Two weeks after Takaichi’s comments, Taiwanese President Lai Ching-te proposed a T$1.25 trillion (US$40 billion), eight-year supplemental package that would raise defence spending to 3.3 percent of GDP. The money would accelerate the military’s transition towards a porcupine force centred on small, mobile and easily hidden equipment.

Yet opposition lawmakers blocked the plan. Cheng Li-wun, who was elected leader of Taiwan’s largest opposition party, the Kuomintang (KMT), in October, dismissed the proposal as ‘too high and too fast’.

This is despite the plan leaving out the large, expensive equipment that the opposition has long said would provoke China. The KMT had previously pledged to support higher defence spending.

Cheng’s position is at odds with the support Taiwan is receiving from its democratic friends. Takaichi’s comments are only the latest example of regional support for Taiwan, which has been increasing this decade. Former US president Joe Biden repeatedly vowed to defend Taiwan, while Donald Trump has said that China would not attack Taiwan during his tenure since it ‘knows the consequences.’

However, these commitments were made on the assumption that Taiwan can withstand an initial wave of Chinese coercion alone and that it demonstrates commitment to its own defence. During the 2024 US presidential election campaign, Trump said Taiwan should spend 10 percent of its GDP on defence, a figure that has since been cited by his administration officials who have urged Taiwan to build up its own defences instead of relying on US support.

Lai’s proposed supplemental defence package seems to have been crafted in direct response to this pressure from the United States. He announced it in a Washington Post op-ed before outlining details in domestic media.

The package has also been designed to placate US concerns about Taiwan’s defence priorities. Under the previous president, Tsai Ing-wen, major expenses on US tanks and fighters and a domestic submarine program were criticised by the opposition as excessive and potentially provocative for China. In contrast, the latest proposal focuses on unmanned vehicles, counter-drone measures, air defences, anti-ballistic missile systems and anti-armour missiles, as well as communication, surveillance and reconnaissance systems.

US senators and the US State Department have expressed approval for the spending plan. De facto US ambassador to Taiwan Raymond Greene called it ‘a major step towards maintaining peace and stability across the Taiwan Strait by strengthening deterrence’. He also warned the KMT and the Taiwan People’s Party, which together hold parliamentary majority, against opposing the plan, saying ‘I expect Taiwan’s political parties will find … common ground’.

Their refusal to review the proposal is proving to be the biggest stumbling block for the plan. Cheng said that ‘such a large rise cannot truly guarantee the security of the Taiwan Strait’.

Such opposition could have a real impact on Taiwan’s credibility and its demonstration of commitment towards its own defence. Alexander Gray, a former Trump National Security Council official, said on 3 December that the package was ‘a long-overdue recognition that the US will only help allies and partners who undertake exceptional efforts to help themselves’. A failure to pass it would send the wrong signal, and potentially leave Taiwan’s partners questioning whether it is worth putting themselves at risk.

Cheng has defended her position, comparing Taiwan with NATO members, which have until 2035 to meet their target defence spending of 5 percent of GDP.

Cheng is known for her provocative statements and wants to strengthen ties with the mainland. She has repeatedly said, ‘I am Chinese’ and has derided the ruling Democratic Progressive Party for spending too much on defence. Taiwan ‘should not be America’s ATM,’ she has said. She wants Taiwan to go back to the 1992 consensus, under which mainland China and Taiwan agree there is only ‘one China’ while taking differing interpretations of what that means.

Takaichi’s willingness to say that a Taiwan conflict would pose a ‘survival-threatening situation’ for Japan is rare and costly for Tokyo. Lai’s defence package is designed to meet that moment. If the opposition blocks it, Taiwan risks undermining partners who are standing up for its security. As Japan and others take greater political risks on Taiwan’s behalf, they expect clarity in return.