For Taiwan this trip by Nancy Pelosi is about support, but also legitimacy.

Taiwan needs America's support, military and otherwise. But it craves legitimacy. It craves recognition that this is not some "renegade province" as Beijing calls it, but a proud country, with its own democratic government and a determination to keep it that way.

That is why a visit by the speaker of the US House of Representatives means so much. America is what Taiwan looks up to, not China.

You can see it in the excited way Ms Pelosi's arrival here is being reported on Taiwan's many TV news channels.

They have been studying everything from the colour of her outfits to the height of her heels - very high for an 82-year-old apparently - and the fact that she "looked like Audrey Hepburn in that photo of her with President John F. Kennedy back in 1961".

There is a full-on Pelosi lovefest happening in Taipei, the island's capital.

Crowds gathered early outside Taiwan's parliament on Wednesday, hoping to get a glimpse of Ms Pelosi as she came out. Almost everyone there brushed off worries that China might retaliate.

"We are used to the threats from China," a female banker told us. "In the long run this trip will be good for the development of US-Taiwan relations."

"China is bluffing," said a 70-year-old man. "It may retaliate in the short term, but if Beijing over-reacts, it will be punished by the United States."

"China shouldn't bully Taiwan like this," a 50-year-old house wife told us. "This trip is normal... if China continues like this it will only alienate more countries."

When President Jimmy Carter recognised the People's Republic of China in 1979, Washington agreed it would drop recognition of the "other" Chinese government in Taipei.

For Beijing, that should have been the end of the story. But America never completely gave up Taiwan. And as this island has transformed from a military dictatorship to a flourishing democracy, the sense that the US should protect this "plucky little democracy" in the face of China's threats has only grown.

It is now increasingly clear that Beijing is not going to be satisfied by venting its anger at Nancy Pelosi's visit to Taiwan with mere words.

The announcement of six large exclusion zones around the island starting on Thursday, and lasting for four days, is ominous. Beijing did the same thing back in 1996, the last time there was a so called "Taiwan Straits Crisis". But then the exclusion zones were all well outside Taiwan's territorial waters.

This time three of the six zones intrude into Taiwan's 12-mile limit. That is unprecedented. Taiwan's defence ministry has already called the move a breach of UN conventions, and said it amounts to an air and sea blockade against the island.

If China were to move ships or aircraft into those areas, it would amount to an invasion of Taiwan territory. This makes the stakes much higher as Taiwan may feel compelled to defend its own waters.

The US Navy is watching all this very closely, and already has the USS Ronald Reagan carrier battle group sailing nearby in the Philippine Sea.

Ms Pelosi is now on her way to South Korea, but the fallout from this trip to Taiwan looks set to rumble on for a while longer - and could even grow in to a major US-China crisis.