Ms Pelosi was due to arrive in Singapore on Monday, following a weekend stop in Hawaii for consultations with US commanders in charge of the Indo-Pacific. She said in a statement that she planned to travel with a congressional delegation for high-level meetings in Malaysia, South Korea and Japan, and did not mention Taiwan. But it would not be unusual for Taiwan to be left out of an announcement due to security concerns, and President Biden’s aides said he was expected to move forward with plans for a top-level US official to visit the island in 25 years. Ms. Pelosi could still change her mind about her trip to Taiwan, administration officials said, but added that it seemed unlikely. Aides to Mr. Biden said he decided not to directly ask Ms. Pelosi to cancel her trip, largely because of his respect for the independence of Congress, forged during his 36 years in the Senate. He is also clearly unwilling to back down in the face of Chinese threats, including Beijing’s warning that the United States is “playing with fire”, which followed Mr Biden’s nearly two-and-a-half-hour conversation with President Xi Jinping. China on Thursday. At its core, some officials said, the administration concluded after the call that the potential domestic and geostrategic risks of trying to stop the visit — including letting China dictate which American officials could visit a self-governing republic of 23 million of people that China claims as its own — was greater than allowing Ms. Pelosi to proceed. But they admitted there was no good information about how strongly China might react. Privately, US officials have urged the Chinese government to avoid the visit, noting that Newt Gingrich visited in 1997 when he was Speaker of the House, and that congressional delegations regularly visit the island to express US support for its defense . But the strategic context of Mr. Gingrich’s trip was entirely different, and in recent years Mr. Xi has made it clear that he considers reunification with Taiwan a priority. US officials were closely watching the Chinese government’s preparations over the weekend, trying to discern Beijing’s intentions. The clearest sign they saw involved the Taiwan Strait, where challenges, trials and signaling are played out every week. China’s military announced Saturday, with less notice than usual, that it will hold live-fire drills in waters off the southeastern province of Fujian, about 80 miles from Taiwan. On Sunday, a Chinese air force spokesman said, without specifying dates, that the country’s fighter jets would fly around Taiwan to demonstrate its ability to defend its territory. That raised the possibility that the exercise would be timed to meet the US Air Force plane carrying Ms Pelosi and her delegation. Their trip was part of a series of efforts to reassure the region that the United States remains committed to its “pivot” to the Indo-Pacific, even as it pours tens of billions of dollars in military aid to Ukraine to bolster it against Russian invasion. American officials doubt that the Chinese military will interfere with Ms. Pelosi’s ability to land safely in Taiwan, betting that Beijing does not want a direct confrontation with the United States. But they say Chinese planes are likely to “escort” Ms. Pelosi’s plane as a show of control over air routes. That raises the possibility, officials fear, of an accident — similar to what happened two decades ago when a Chinese air force jet collided with and shot down a U.S. spy plane, leading to an early crisis in the George W. Bush administration.

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Officials say they have no reliable information about what the Chinese government may be planning. But they expect the biggest response could come after Ms Pelosi leaves and could include military maneuvers in the Taiwan Strait, cyber attacks or a communications blackout that would demonstrate Beijing’s ability to suffocate the island, which is also its the world’s – and China’s – largest supplier of the world’s most advanced semiconductors. In recent weeks, US intelligence officials have warned that China may be preparing to act against the island sooner rather than later. Intelligence analysts have concluded that China may fear that the United States’ commitment to help turn the island into a “skunk” — armed with weapons like those provided to Ukraine to fend off the Russians — might make Mr. Xi and his army to think that they must move within the next 18 months, lest they lose the military advantage. A move could include an incident in the Straits or an attempt to squeeze and isolate the island, short of a full invasion. But the warning is based more on analysis, officials say, than new discoveries of information. William J. Burns, the CIA director, said in July that China seemed “disturbed” by Russia’s struggles in Ukraine and may conclude it needs to develop “overwhelming” capabilities before considering any move against Taiwan. Ms. Pelosi has a long history of protesting human rights abuses by the Chinese government during her career in Congress. Thirty-one years ago he visited Tiananmen Square and unfurled a banner commemorating the hundreds of protesters who had been killed there by Chinese troops in 1989, deeply angering the Chinese leadership. Three times since taking office, Mr. Biden has also rattled Beijing with what could have sounded to Chinese leaders as a hardening of America’s commitment to Taiwan’s defense — and a rejection of carefully worded ambiguity about how much could help Taiwan in the event of a military attack. The most recent came in late May, when Mr. Biden surprised a gathering of Asian leaders by saying “yes” when a reporter asked if he “would be willing to get involved militarily to defend Taiwan.” Mr. Biden never clarified what the phrase meant in his mind, and White House officials insisted that US policy had not changed. Ms. Pelosi has not confirmed whether she will visit Taiwan. But she had proposed a trip to the island this year, which was postponed because she contracted the coronavirus, and when asked recently about her travel plans, she said “it’s important for us to show support to Taiwan.” On Sunday, Ms. Pelosi revealed a few more details about her itinerary that she had previously declined to reveal, citing security concerns. Her office said her trip would focus on “mutual security, economic partnership and democratic governance in the Indo-Pacific region”. A post on the website of the American Chamber of Commerce in Singapore said Ms. Pelosi would attend a cocktail reception attended by the group on Monday afternoon. Mr Xi, China’s most authoritarian leader in decades, has pledged to pursue reunification with Taiwan, although he has not specified a timetable. Some analysts fear he may feel pressure to show a tough stance — possibly including military action — against any perceived challenges to that commitment ahead of a major Chinese Communist Party congress this fall, when he is expected to seek a third term as leader. However, other analysts have played down the risks of military escalation, arguing that Mr Xi would likely want to avoid contingency ahead of the meeting. Mr. Biden himself has seemingly referred to the risk of conflict with China should Ms. Pelosi visit. Asked by reporters recently about the proposed trip, he said “the military doesn’t think it’s a good idea at this time.” The president is also strengthening US relations with Asian allies as a possible counterweight to China’s rise. A Chinese Foreign Ministry spokesman, Zhao Lijian, told reporters last week that China would take “firm and decisive measures” if Ms. Pelosi visited Taiwan and that the United States would be “responsible for all serious consequences.” Some political analysts and state media commentators have suggested that China will activate its air force to prevent the visit – raising the specter of armed conflict. The Biden administration insists its stance on Taiwan has not changed, a message Mr. Biden conveyed to Mr. Xi during their phone call, according to the White House. Longstanding American policy recognizes, without endorsing, China’s position that Taiwan is part of its territory, and maintains that the United States will protect the island without saying exactly how. But the president has little formal authority over Ms. Pelosi and her travel plans. And growing anti-Chinese sentiment in both the Democratic and Republican parties makes it politically difficult for Mr. Biden to openly discourage her trip. Domestic politics, both in China and the United States, have left little room for graceful de-escalation, said Chen Qi, a professor of international relations at Tsinghua University in Beijing. It could cost Democrats politically if Ms Pelosi decides not to visit Taiwan, Professor Chen said in an interview with a reporter for Xinhua, China’s state-run news agency. And China cannot afford to be seen as weak in the face of a daunting challenge. “Now it depends on who blinks first,” said Professor Chen. Edward Wong contributed reporting. John Liu and Claire Fu contributed to the research.