Nancy Pelosi has embarked on a tour of East Asia that officials signalled on Monday was likely to include a stopover in Taiwan, the first by a US House Speaker for 25 years. China warned that its military will “not sit idly by” if the visit goes ahead to the self-ruled island that Beijing claims as part of its sovereignty. Though Washington has a right to try to shore up Taiwan’s position and discourage Chinese aggression, the Speaker’s visit is ill-conceived and ill-timed. If it goes ahead, this is a moment of danger that calls for responsibility and restraint from both sides.

The risks of Pelosi’s visit should not be underestimated. Xi Jinping, China’s powerful leader, warned US president Joe Biden last week that the US was “playing with fire”. According to Beijing’s official statement, Xi did not mention Pelosi’s name but said his government would “resolutely safeguard China’s national sovereignty and territorial integrity”.

The visit comes at a highly-charged moment. Xi is seeking another term in office at the 20th National Congress of the Chinese Communist party later this year. Yet internal tensions are high as the economy stumbles and Beijing’s “zero-Covid” policy attracts criticism.

It is not yet clear if China will launch retaliatory measures over Pelosi’s trip. In the mid-1990s, Beijing expressed ire over an unofficial visit to the US by the independence-minded Taiwanese president Lee Teng-hui by test-firing missiles into the sea near the island.

Beijing warned last month that a visit by Pelosi would represent a “serious violation” of “One China” policy, under which the US recognises the People’s Republic as the sole legal government of China, but only acknowledges Beijing’s position that Taiwan is part of China. Beijing’s assertion in the 1990s that Lee’s visit to the US breached the One China policy prompted the missile crisis across the Taiwan Strait.

There is, to be sure, good reason for senior US officials to want to show solidarity with Taiwan. Xi has been increasingly vocal in his insistence that Beijing has the resolve and means to achieve “complete reunification” of the island with the “motherland”. Beijing has stepped up military pressure on Taipei, including repeatedly sending warplanes into Taiwan’s air defence zone.

Pelosi has also done much to highlight China’s human rights abuses during her career, including unfurling banners in Tiananmen Square in 1991 in protest at Beijing’s 1989 massacre of civilians. Today, however, Taiwan represents a much more complex geopolitical issue. The risks of war across the Taiwan Strait, and that any conflict could end up pitting China against the US, are real.

Pelosi’s visit is in danger of being seen as a grandstanding act that will incense Beijing without improving the security of Taiwan’s 24m people. The dilemma for the Speaker now is that while going ahead with the trip carries dangers of retaliation by Beijing, not doing so would risk being seen as submitting to Chinese pressure and giving Beijing a say in how the US can engage with Taiwan.

If the trip takes place, China should think long and hard before unleashing any form of aggression in response. It should be aware that Congress and its Speaker are separate from the US executive, and Pelosi’s visit carries no official endorsement. Indeed, the White House made clear last month that US policy on Taiwan had not changed.

The US should in future focus on carefully-co-ordinated actions that have genuine value in shoring up Taiwan’s security. Washington should step up supplies of weapons, as provided for under the 1979 Taiwan Relations Act, and expand training. Such moves, undertaken without fanfare, are likely to be much more effective than high-profile but ultimately empty visits.