In what can only be interpreted as a calculated provocation against China, the US navy sent two destroyers through the Taiwan Strait last Saturday. The key strategic waterway, which is about 130-220 kilometres wide, lies between mainland China and Taiwan, which Beijing claims at part of its territory.

Significantly, it was Taiwanese, rather than American, officials who first announced the sensitive transit by the USS Mustin, a guided missile destroyer, and the USS Benfold, an anti-aircraft destroyer. The brief Taiwanese announcement is a further indication of the closer relations that the Trump administration is forging with Taiwan, including potentially military ties.

The naval transit coincided with the escalating trade war between the US and China. The Trump administration implemented its 25 percent tariff on $34 billion worth of Chinese imports last Friday. China is retaliating with tariffs on an equal amount of US products, including soybeans, electric cars and pork.

Pentagon spokesman Colonel Robert Manning declared that the US navy has a “right” to sail through international waters but declined to comment on the timing of the passage. “We can fly, sail and operate where we want,” he said. “That’s legally permissible.”

While the US navy might have the legal right of passage, it rarely deploys warships through the Taiwan Strait. It has sent an aircraft carrier through the sensitive waterway just twice in recent years—in 1996, in the midst of high tensions with China over Taiwan, and in 2007.

Under conditions where the US is strengthening ties with Taiwan, the Trump administration and the Pentagon are well aware that the dispatch of warships through the Taiwan Strait will provoke condemnation from China.

In December 2016, prior to assuming office, Trump specifically questioned US observance of the One China policy, under which Washington recognises Beijing as the legitimate ruler of all China, including Taiwan. “I don’t know why we have to be bound by a One China policy,” he declared, “unless we make a deal with China having to do with other things, including trade.”

Having taken office, Trump provocatively took a phone call from Taiwanese President Tsai Ing-wen, the first direct contact between US and Taiwanese leaders for nearly four decades. In March this year, Trump signed into law the Taiwan Travel Act, which encourages US officials at all levels to travel to Taiwan and permits high-level Taiwanese officials to enter the US for talks, including on military matters. The US has also opened a new building and compound for the American Institute in Taiwan, which operates as the de-facto embassy in Taipei.

Diplomatic relations between the US and Taiwan ended in 1978 when the US adopted the One China policy, while at the same time legislating to defend the former ally militarily against any move by China to forcibly incorporate the island. In acknowledging the One China policy, Washington has, until now, been cautious about any formal contact.

For Beijing, which regards Taiwan as a renegade province and has threatened to use force if it should ever formally declare independence, the US strengthening of ties with Taipei, including militarily, is a highly sensitive issue. Any move by Taiwan, backed by the US, to assert independence threatens to encourage similar steps by separatist organisations in the Chinese regions of Tibet and Xinjiang.

Beijing criticised the latest passage of US warships through the Taiwan Strait.

Chinese Foreign Ministry spokeswoman Hua Chunying said China had followed the ships’ movements and had “expressed concerns” to the US. “We must state, the Taiwan issue is related to Chinese sovereignty and territorial integrity,” she told reporters. “We urge the United States to at once scrupulously abide by the One China principle... and avoid harming China-US relations and peace and stability in the Taiwan Strait.”

Liu Jieyi, director of China’s Taiwan Affairs Office and former Chinese ambassador to the United Nations, said the US had been using the Taiwan “card” for some time. “We staunchly oppose any move that harms China’s national interest. We won’t accept that,” he said. An editorial in the hawkish state-owned Global Times accused the US of playing a “psychological game” by sailing the two destroyers through the Taiwan Strait, adding to tensions with China and throughout the region.

The moves by the US to strengthen ties with Taiwan are part of Washington’s aggressive drive to trade war and war in a bid to ensure American domination in Asia and internationally. This includes the US military’s provocative “freedom of navigation” operations to challenge Chinese territorial claims in the South China Sea and its efforts to bully and bribe North Korea via nuclear negotiations to shift away from China and toe the line set by Washington.

Last Friday and Saturday, US Secretary of State Mike Pompeo held the first round of talks with North Korean officials since Trump met with North Korean leader Kim Jong-un in Singapore last month. Pyongyang’s denunciation of Washington’s “gangster-like” demands indicates that Pompeo delivered what amounted to an ultimatum to North Korea to accede to the entire US agenda or face the prospect of war.

Pompeo and Trump both dismissed the North Korean condemnation, with Trump suggesting that China was meddling in the nuclear negotiations between the US and North Korea. “I have confidence that Kim Jong Un will honor the contract we signed &, even more importantly, our handshake,” Trump tweeted, adding: “China, on the other hand, may be exerting negative pressure on a deal because of our posture on Chinese Trade. Hope Not!”

As the US seeks to encircle China and prepare for war, Taiwan is a key aspect of its strategy. Its step-by-step strengthening of ties with Taipei is not simply a ploy to put pressure on Beijing. In the event of war, Taiwan would be a key strategic stronghold just off the Chinese mainland.

In the latest step to forge military ties, the US Senate Armed Services Committee passed a draft bill in May calling for American troops to participate in Taiwan’s most important annual war games—the Han Kuang military exercises that are now underway. While the Pentagon no doubt quietly collaborates with its Taiwanese counterparts, such legislation pushes for direct and open military exchanges.

The draft legislation is another indication of the push towards the incorporation of Taiwan into the web of alliances and strategic partnerships in the Indo-Pacific region targeted against China.