An island 200 kilometres off the coast of China looms as the biggest international test of the Biden administration and Beijing’s relationship with the world. Characterised by its liberal democracy, resilient economy and the existential threat of invasion, Taiwan has lived under a cloud for more than half a century.

Its existence has seen Taiwanese and Chinese diplomats come to blows over a cake decorated with a Taiwan flag in Fiji, a Perth theatre forced to apologise to Chinese officials over a diplomatically sensitive performance and Qantas remove Taiwan from its list of country destinations.

Long a diplomatic flashpoint, it now threatens to become a military one.

Seven months after Hong Kong was subdued by the Chinese Communist Party, Beijing has turned its attention to the final territory not in its control under the “One China policy”, sending dozens of warplanes over the Taiwan Strait to mark the start of 2021.

Senior colonel Wu Qian, China’s Ministry of National Defence spokesman, issued a warning days after fighter jets and bombers harassed the Taiwan Strait’s median line in January.

“We solemnly warn these Taiwan separatists: those who play with fire will get burnt, Taiwan secession means war,” Wu said.

Why does China have Taiwan in its sights? What does Taiwan want? And, as tensions rise, how would the US – and Australia – be likely to respond?

Why does China hate Taiwan?

Taiwan split from the mainland after years of civil war between two rival political forces: the Chinese Communist Party and the Kuomintang. The Kuomintang fled to Taiwan in 1949, along with two million civilians. It established a government in Taipei after the Chinese Communist Party’s leader, Mao Zedong, proclaimed the founding of the People’s Republic of China in Beijing.

China has never recognised Taiwan’s government and has set a deadline of 2049 for unification of the mainland with the island.

Taiwan’s government also claimed China as its territory under its constitution in 1949, creating a diplomatic minefield for foreign governments. The United Nations recognised Taiwan’s claim until 1971, before switching to China as diplomatic relations were established with the Chinese Communist Party.

“Taiwan has not for one single second belonged to China,” says the co-chair of Taiwan’s Foreign Affairs and Defence Committee, Wang Ting-yu.

“The Chinese Communist Party never had a single cent of tax paid from Taiwan but the past 40 years they have been using their diplomatic tactics and military threats to disturb Taiwan’s society.”

The Taiwanese Public Opinion Foundation found support for official independence for Taiwan, which could involve relinquishing its claim to the mainland in the constitution, had reached its highest level in July 2020. Some 54 per cent of respondents said Taiwan should become officially independent while 23.5 supported maintaining the status quo. Only 12.5 per cent supported unifying with the mainland.

So, is Taiwan a country?

That depends on who you ask. Australia has not recognised Taiwan as an independent nation since it established diplomatic relations with Beijing in 1972, which stipulated that the Chinese government had legal sovereignty over Taiwan and acknowledged Taiwan was a province of China.

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Only 15 countries recognise Taiwan as an independent government, Nauru, Nicaragua and Palau among them. For their trouble, they have no diplomatic contact with China, the world’s second largest economy. In September 2019, under the promise of economic investment and aid, Kiribati and the Solomon Islands switched their allegiance to Beijing.

Taiwan’s status is both fundamental to its government and its people at the same time as its proximity to an increasingly assertive China puts it in a geopolitical pincer. The difficulty that has plagued the foreign policy of governments around the world is how they defend a country that they do not recognise.

The island’s status as a liberal enclave in the mouth of an authoritarian state may become more important than any diplomatic label. It is now the democratic frontier.

Is Taiwan the next Hong Kong?

Hong Kong was handed back to China in 1997 after colonial occupation by the British. It was guaranteed a high degree of autonomy in its executive, legislative and independent judicial power but China has been accused of breaching the handover treaty by instituting national security laws that effectively wipe out Hong Kong’s political opposition.

The laws, which followed more than a year of protest over Beijing’s rising influence, were able to be implemented because Hong Kong’s government and its police force were complicit in the crackdown on the semi-autonomous region’s pro-democracy movement.

Taiwan, where President Tsai Ing-wen won a landslide election on a platform of remaining separate from China in January 2020, is a very different proposition.

Mark Harrison, a Taiwan expert from the University of Tasmania, says public opinion remains resolute. “The people of Taiwan have been pursuing self-determination for more than a hundred years and Beijing’s actions won’t alter that long-standing historical aspiration,” he says.

Unlike Hong Kong, where China avoided sending in tanks to suppress dissent, taking Taiwan by force may be Beijing’s only option if it is to meet its target of “reunification”.

Lowy Institute fellow Natasha Kassam says even the word “reunification” is itself a product of the China’s propaganda department. Taiwan, since it split from the mainland in 1949 has never been under the control or jurisdiction of the Chinese Communist Party.

“China tries to make others use reunification to make Taiwan’s seem inevitable to the outside world,” she says. “But unification or even annexation is more accurate.”

China’s Ministry of Foreign Affairs regularly makes its position on the “Taiwan question” clear. “There is but one China in the world, and the Taiwan region is an inalienable part of the Chinese territory,” Foreign Ministry spokesman Zhao Lijian said in mid-January, days after the People’s Liberation Army flew dozens of fighter jets over the Taiwan Strait.

“China is determined in safeguarding national sovereignty and territorial integrity, and opposing ‘Taiwan independence’ and interference by external forces.”

Is Taiwan in a strategic position?

Apart from its symbolic stature, Taiwan’s geographic position makes it vital to the defence of East Asia and the South China Sea.

Japan, when it occupied Taiwan between 1895-1945, used the island to launch attacks on the Philippines and Indonesia at the same time as it bombed Pearl Harbour during World War II.

The island gives critical access to the Taiwan Strait, one of the world’s busiest shipping lanes, and also allows submarines to be launched directly into deep waters, opening the door to the Pacific and the South China Sea.

Joseph Bosco, a former China desk officer for the US Secretary of Defence, says China’s coastline in the East China Sea lacks deep-water ports.

“Its submarines must operate on the surface until they are able to submerge and dive deep when they reach the area of the Ryukus archipelagoes [near Japan],” he noted for The Diplomat.

“If China controlled Taiwan, its submarines would have a far easier exit from Taiwan’s deep-water ports into the Pacific.”

Why is China threatening Taiwan but not actually attacking?

China has sharply escalated its military incursions over the Taiwan Strait in the past year.

The median line that splits the disputed zone has been breached hundreds of times by Chinese bombers, fighter jets and surveillance aircraft.

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Over one weekend in mid-January 2021 two dozen warplanes flew over the strait, including two anti-submarine aircraft, four J-16 strike fighters and six J-10 fighter planes.

The number of incursions in 2021 is expected to dwarf the level in previous years. Each time a Chinese plane crosses the median line, a Taiwanese plane is scrambled to meet it.

Taiwan’s National Defence Minister, Yen Teh-fa, estimated this cost $1.2 billion in 2020 alone.

The tactics are part of what is known as “grey zone warfare” where the goal is to wear down opposition rather than spark an immediate conflict.

“You say it’s your garden, but it turns out that it is your neighbour who’s hanging out in the garden all the time,” Taiwan’s former military commander Admiral Lee Hsi-ming told Reuters in 2020. “With that action, they are making a statement that it’s their garden – and that garden is one step away from your house.”

The inauguration of Joe Biden as President of the United States in January encouraged Beijing to push the envelope further, examining the new administration’s resolve after a fractious four years in US-China relations under his predecessor Donald Trump.

“The recent actions are a systematic escalation of the round of military intimidation that began last year but will also factor in an intention to test the Biden administration,” Harrison says.

They are also part of a suite of measures used in the grey zone, including cyberattacks, propaganda and infiltration of pro-independence sentiment.

China’s Overseas United Front Work Department updated its regulations in January for Chinese citizens living abroad, urging them to work within their communities to rally against pro-Taiwan forces.

It “implored its overseas citizens to curb Taiwan independence” and safeguard the core interests of the country.

Wang, the Foreign Affairs and National Defence Committee co-chair, said in the short-term the greatest risk was the psychological threat of China’s grey-zone tactics undermining confidence in Taiwan’s own defence.

“They can harass us, they can attack our remote islands and fire some missiles to scare the stockmarket but if the Taiwanese psychological defensive line breaks, that is another scenario,” he says.

That is why the build-up of Taiwan’s defence is as much a military deterrent as it is a psychological boost to its 24 million people. They have lived under a constant threat of attack for decades and will continue to do into the distant future.

The next five years are crucial. Why?

China has been rapidly expanding its military and naval power, sending army officers for training on naval ships to expand its amphibious capability and investing in new military technology at a record level.

It has more than 1 million members of its armed forces (to Taiwan’s 150,000), more than 5800 tanks and 1500 fighter jets.

But Wang said on Taiwan’s estimates the People’s Liberation Army still does not have enough firepower to mount a successful invasion and occupation of Taiwan for at least the next five years.

China does not yet have the number of tank landing ships required to land on Taiwan’s beaches, traverse hostile terrain, occupy and hold the capital Taipei, which is surrounded by mountains. There are only a dozen beaches suitable for invasion of that scale and only 37 ships available at this point. The Taiwanese defence force has spent decades building up these beaches against this threat, making any potential invasion bloody and costly.

The US is also bolstering its arms sales to Taiwan in an attempt to keep up with China’s expansion. The goal is to offer enough protection to at least act as a deterrent. In one deal it sold $2.4 billion worth of rocket launchers, artillery and missiles to Taiwan in 2020.

“China would have to ferry and sustain by sea and air an army large enough to seize and hold an island with 24 million people,” the US former deputy assistant secretary of defence Elbridge Colby wrote in The Wall Street Journal in January.

“This might be feasible if the PLA attacks a Taiwan standing alone. But taking Taiwan backed up by a well-prepared US military is a far different proposition. Amphibious invasions against a capable, prepared defence are very hard.”

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How would the US respond if there was an attack?

Weeks before the end of the Trump presidency, the US government declassified a key document decades before it was due to be made public: its Indo-Pacific strategy.

The document says the US will devise and implement a defence strategy capable of: “(1) denying China sustained air and sea dominance inside the ‘first island chain’ in a conflict; (2) defending the first island chain nations, including Taiwan; and (3) dominating all domains outside the first island chain.”

Biden has maintained his commitment to Taiwan is “rock solid”. The US rhetoric has suggested it will continue and enhance Trump’s Indo-Pacific policy and support action against China if it attempted to launch an attack.

Significantly, Biden invited Taiwan’s de-facto ambassador to Washington, Hsiao Bi-khim, to his inauguration. It was the first time a Taiwanese leader had been invited to the marquee presidential event.

Three days after the inauguration the US took three other symbolic steps.

Within hours of Taiwan intercepting another dozen warplanes flying over the strait, the US State Department warned Beijing against harassing its neighbours and allies. Then it sent the US aircraft carrier Theodore Roosevelt to the South China Sea, and finally the new US Secretary of Defence Lloyd J Austin made two phone calls, his first after NATO and the United Kingdom.

They were to his counterparts Nobuo Kishi in Japan and Suh Wook in South Korea. “That is sending a strong clear signal that the Indo-Pacific will be the top priority,” says Wang.

“Not the Middle East.”

His next phone call was to Australian Defence Minister Linda Reynolds.

Austin said it reaffirmed “The Unbreakable Alliance,” a step up from the “100 years of mateship” that Australian leaders have used to characterise the relationship.

“The US and Australia stand together as mates, as we have for over 100 years, ready to face the challenges and threats to a free and open Indo-Pacific,” Austin said on Twitter.