Roy Blunt lived up his surname when he said this week: “So I’m about to use four words in a row that I haven’t used in this way before, and those four words are: ‘Speaker Pelosi was right.’”

The Republican senator was praising Nancy Pelosi’s visit to Taiwan, the first by a speaker of the US House of Representatives in a quarter of a century.

But not everyone was so sure. In poking the hornets’ nest and enraging China, which claims the self-governing island as its territory, Pelosi deepened a rupture between the world’s two most powerful countries – and may have hurt the very cause she was seeking to promote.

On Thursday, China fired multiple missiles into waters surrounding Taiwan and began a series of huge military drills around the island; the White House summoned China’s ambassador, Qin Gang, to protest. On Friday, China said it was ending cooperation with the US on key issues including the climate crisis, anti-drug efforts and military talks.

It was yet another moment of peril in a world already reeling from the coronavirus pandemic, Russia’s war in Ukraine and mass food shortages.

So why did Pelosi go? The speaker is a fervent defender of Taiwan and critic of China’s human rights abuses. During the visit, she pointed to a global struggle between autocracy and democracy, a favourite theme of Joe Biden’s, and told reporters in Taipei: “We cannot back away from that.”

But the 82-year-old may also have been rushing for a last hurrah before November’s midterm elections in which she is expected to lose the speaker’s gavel. Her televised meetings in Taiwan, sure to have registered in Beijing, appeared to some like a vanity project.

Writing just ahead of the trip, Thomas Friedman, an author and New York Times columnist, described Pelosi’s adventure as “utterly reckless, dangerous and irresponsible”, arguing that Taiwan will not be more secure or prosperous because of a “purely symbolic” visit.

Friedman warned that the consequences could include “the US being plunged into indirect conflicts with a nuclear-armed Russia and a nuclear-armed China at the same time”, without the support of European allies in the latter.

Biden himself had publicly admitted that the US military felt the trip was “not a good idea right now”, not least because President Xi Jinping is preparing to secure a third term at the Chinese Communist party’s national congress later this year.

In a call last month, the White House has said, Biden sought to remind Xi about America’s separation of powers: that he could not and would not prevent the speaker and other members of Congress traveling where they wish.

But Biden and Pelosi are close allies from the same political party, a different scenario from 1997 when Democrat Bill Clinton was president and Republican speaker Newt Gingrich went to Taiwan. Pelosi, second in line to the presidency, flew into the island on a US military aircraft with all the government heft that implies.

It was perhaps telling that Biden and Democrats remained mostly silent, whereas the speaker’s loudest cheerleaders were rightwing Republicans and China hawks including Gingrich.

Some commentators believe that a superpower conflict between America and China over Taiwan or another issue is one day inevitable. White Pelosi may have shaved a few years off that forecast, it could be argued that Biden himself has supplied some of the kindling.

For months the president has sown doubts about America’s commitment to the “One China” policy, under which the US recognises formal ties with China rather than Taiwan. In May, when asked if the US would be get involved military to defend Taiwan, he replied forcefully: “Yes. That’s the commitment we made.”

Although America is required by law to provide Taiwan with the means to defend itself, it has never directly promised to intervene militarily in a conflict with China. This delicate equilibrium has helped deter Taiwan from declaring full independence and China from invading. But some worry that Biden is supplanting this longstanding position of “strategic ambiguity” with “strategic confusion”.

Bonnie Glaser, director of the Asia Program at the German Marshall Fund of the United States thinktank in Washington, told a Council on Foreign Relations podcast this week: “There has been a lack of clarity, consistency, a lack of discipline, shall we say, and even a lack of coherency, I think, in US policy statements.

“The Biden administration continues to say that the United States has a One China policy, that the United States does not support Taiwan independence, but then there are other things that the US does, which from China’s perspective and using their language, looks like we are slicing the salami. We are heading towards supporting a Taiwan that is legally independent.”

Glaser added: “So Speaker Pelosi going to Taiwan doesn’t really, I think, in and of itself cross a red line, but I think the Chinese see a slippery slope … And then on top of all this, we have President Biden talking about policy toward Taiwan in confusing ways.”

Other analysts agreed that, once news of Pelosi’s plan to visit Taiwan emerged, it would have been impossible to back down without handing Beijing a propaganda victory.

Bill Galston, a senior fellow at the Brookings Institution thinktank and former policy adviser to Clinton, said: “I can see the arguments on both sides. Argument on one side, this was probably an ill-timed gesture on her part. Argument on the other side, once the issue was joined, allowing the Chinese to bully her out of the trip would would have been a really bad sign to the region.

“If she hadn’t put the issue on the table, that would have been one thing. But once she did and once it was clear that she was pretty firm in doing it, it would have been a mistake, say, for the president to put a lot of pressure on her not to go. That would have been both a substantive mistake and a political mistake.”

Larry Diamond, a senior fellow at the Hoover Institution thinktank in Palo Alto, California, wrote in an email: “Pelosi wanted to convey our commitment and resolve. I respect her for that. However, I still think the trip was a mistake. It provoked a serious escalation of Beijing’s military intimidation without really doing anything to make Taiwan more secure.

“What Taiwan really needs now is more military assistance, especially a large number of small, mobile, survivable and lethal weapons, like anti-ship missiles. To paraphrase [Ukraine’s Volodymyr] Zelenskiy, they don’t need more visits, they need weapons. And they have to do a lot more themselves to prepare for a possible attack.”