On Donald Trump’s flight home from his visit to China, all that the journalists wanted to know was whether he had talked to President Xi Jinping about Taiwan. China has been pushing hard for the United States of America to cancel its military commitment to the island state, and Trump has been hinting that he may at least downgrade it.

The journalists popped the question, focussing on the $14 billion US arms sale to Taiwan that is currently awaiting approval. He must have known that the question was coming, but he replied as follows: “... I have to speak to the person that right now is, you know, you know who he is, that’s running Taiwan.” (The president of Taiwan is Lai Ching-te.)

Trump couldn’t even remember the man’s name — and he also seemed to say that he was in two minds about delivering on the previous $11 billion arms sale to Taiwan. In the following days, there has been a noisy debate in the US about whether Trump is selling Taiwan out to China, but it’s a bit late. Any US commitment to defend Taiwan militarily died years ago.

To be specific, it died on February 24, 2022, when Russia invaded Ukraine and the US did not come to its defence. True, Ukraine is not officially an American ally, but then neither is Taiwan. (Joe Biden often forgot and said that the US was committed to defending Taiwan, but his advisers would quickly walk it back.)

What used to exist was an unwritten understanding that the US would defend Taiwan against an invasion by the People’s Republic of China. Initially, it was only unwritten because Beijing gets cross if Washington uses those words, but by Biden’s time, there was real doubt that the US would fight for Taiwan. And then came the war in Ukraine.

Biden made the right choice. Four years later, Ukraine is still standing, and there have been no direct confrontations between Russian and American troops. But if the US won’t even risk a war with Russia, then it certainly won’t risk one with China, which is a far more formidable opponent. In Europe, the US has an entire alliance to back it up (although Trump is talking about leaving NATO). Its Asian allies will not send troops to save Taiwan.

So is Taiwan doomed? Not necessarily, although the odds against its survival as a separate country have worsened. Taiwan’s numbers seem hopeless (23 million Taiwanese versus 1.4 billion citizens of the PRC). But it has a secret weapon. The Taiwanese live on a big island, with more than 150 kilometres of open ocean between them and the PRC.

“Oh God! Not another Strait!” I hear you cry, but the Strait of Taiwan works to the country’s advantage. In terms of sea conditions, you might as well be in the open Pacific, and the island gets hit by three or four typhoons every year. The strait is quite shallow and easy to mine, and the beaches are a nightmare for any attacker trying to land troops.

Where the Normandy beaches of D-Day were wide and flat, Taiwan’s coastline has mud flats, cliffs and urbanised areas. There are only 14 stretches along the west coast where landing craft can come ashore, and everybody in the military knows where they are. As for paratroops, they only carry light weapons and quickly run out of supplies.

Taiwan could not win a war against China, but a seaborne invasion against entrenched opponents is the most difficult military operation. If the Chinese regime will not use nuclear weapons against fellow Chinese (which one assumes it will not), it’s possible that Taiwan could stay largely unconquered for months.

The Taiwanese certainly can’t do that now — they have long been free-riding on the imaginary American ‘guarantee’ — but they could do it in two or three years if they are willing to spend the money and the US remains willing to sell them arms (nobody else will). They still couldn’t ‘win’, but they could negotiate a lot better terms for a ceasefire. Look at what the Iranians did.

Gwynne Dyer’s new book is Intervention Earth