Having landed in Taiwan amid soaring tensions with China’s military, the US House speaker, Nancy Pelosi, defended her controversial trip to the self-ruling island, saying she was making clear that American leaders “never give in to autocrats” in an opinion piece published in the Washington Post.

“We cannot stand by as [China] proceeds to threaten Taiwan – and democracy itself,” said Pelosi’s piece, published just as the veteran California congresswoman’s plane touched down on Tuesday. “Indeed, we take this trip at a time when the world faces a choice between autocracy and democracy.”

Given that Pelosi’s trip presents a serious diplomatic headache for the Joe Biden White House, there had been much speculation about the motivations behind the controversial visit. In her op-ed Pelosi struck a hard line against China’s position that her trip was a provocation and placed it in the context of a broader global struggle over political freedom.

In the article Pelosi said: “We take this trip at a time when the world faces a choice between autocracy and democracy. As Russia wages its premeditated, illegal war against Ukraine, killing thousands of innocents – even children – it is essential that America and our allies make clear that we never give in to autocrats.”

Pelosi’s visit to Taiwan is unfolding during a tour of Asian nations this week. Her diplomatic mission aims to punctuate a foreign policy career that has seen her defend human rights and democratic values abroad. But it has infuriated China, which claims Taiwan as a province of its own and has threatened retaliation over the visit. The US officially supports a “one-China” policy but in practice treats Taiwan as an economic and democratic partner.

She is the highest-ranking US official to visit Taiwan since the Republican Newt Gingrich went there as the House speaker in 1997, going there even after Biden recently said the American military did not think it was a good idea for her to travel there.

Chinese state media reported that fighter jets were flying across the Taiwan strait just as Pelosi’s plane landed in the island’s capital, Taipei.

Analysts do not expect China to follow through with a hostile military act, at least not while Pelosi is there. But already on Tuesday authorities in China had announced a ban on imports from more than 100 Taiwanese food companies, which many had interpreted as retribution over Pelosi’s trip.

If her piece in the Washington Post is any indication, none of it fazed Pelosi, who in 1991 unfurled a banner in Beijing’s Tiananmen Square hailing the pro-democracy student activists killed there two years earlier.

Pelosi’s op-ed said it was 43 years ago that the US Congress passed an act recognizing Taiwanese democracy that thenpresident Jimmy Carter signed into law.

“It made a solemn vow by the United States to support the defense of Taiwan [and] to consider any effort to determine the future of Taiwan by other than peaceful means … [a] grave concern to the United States,” Pelosi’s piece added, noting that her trip sent an important message nearly six months after Russia invaded Ukraine and unbalanced global peace.

“Today,” Pelosi continued, “America must remember that vow. We must stand by Taiwan, which is an island of resistance.”