Some analysts see America entering a period of "managed decline" not unlike that which Britain has experienced since the end of the Second World War and the end of empire.

Since the Chinese economy began to open up a quarter of a century ago, there are 400 million fewer desperately poor people in China. Now Beijing wants the remarkable domestic growth story to count for something in global terms. China has already overtaken Britain and France to become the world's fourth largest economy and Mr Hu's visit to Washington represents a culture clash on a global scale. China, the emerging Asian superpower, is ruled with an iron fist by the Communist Party, which has transformed a once centrally planned economy into a free market one, "socialist with Chinese characteristics".

What China repeatedly calls its "peaceful rise" represents a major challenge for the US economy, for its political position and for its role as global policeman.

China, with its endless supply of goods and its thirst for energy, has contributed more to global growth than America in recent years, and Beijing is well aware of this. Mr Hu's visit to America is about boosting China's prestige, earning respect for the world's fastest-growing major economy and matching some of that financial muscle with real political influence.

Japan remains the engine of the Asian economy but it is not registering anything like the double-digit growth rates that China is seeing every year. What makes the rise of China different from Japan's post-war emergence is that China can match its economic growth with a strong army. China is no defeated nation, struggling out of the ashes; instead it is a proud country which likes to remind others of its cultural achievements over thousands of years.

More than half of all industrial goods are made in its factories. The production and export of these goods, their prices kept low by Beijing's manipulation of the renminbi currency, has generated the cash behind China's growing economic power.

Mr Hu was all business at the start of his tour. Dinner at Bill Gates' house in Seattle, followed by a café latte with Howard Schultz, chairman of the Starbucks chain of coffee shops, then on to the Boeing plant, before moving to the east coast, with an itinerary that includes a speech at Mr Bush's alma mater, Yale.

But this opening has been undermined before Mr Hu even arrives. The Chinese leader is being given full military honours on arrival but Mr Hu's journey is not being labelled an official "state visit" as such, but something further down the chain.

Face matters in Asia, and some are reading this as a loss of face for Mr Hu. A dangerous move perhaps, given the shape of things to come. For the Bush administration, the key issue is a huge trade imbalance which is turning ever more political. Cheap Chinese exports are flooding the US market and costing American jobs.

And it is ideological too. China is not a democracy, its attitude on human rights leaves a lot to be desired and the Communist Party's treatment of organised religions angers the devoutly Christian Mr Bush. The feeling in Washington is that Beijing needs to do more to stave off the nuclear threat of North Korea and Iran, while China's courting of oil-rich, but politically suspect, countries in Africa and central Asia also rankles. A mixed bag of complaints, and the perceived absence of a clear line on China has angered some US lawmakers. The Senate Democratic leader, Harry Reid, said that Mr Bush "still has no coherent strategy for managing this nation's relationship with China".

The war in Iraq or Iran's nuclear ambitions are side issues compared with the question about China's "peaceful rise" and what to do when it decides to flex its muscles. Keen to keep the spin positive, senior Chinese foreign affairs officials said Mr Hu's visit would "provide an opportunity for Americans to better understand China's policy of seeking sustainable development and peaceful growth".

The trip will also introduce Mr Hu to the world. He remains a bit of a mystery three years into his leadership and little is known about his personal life, beyond the fact that he is frugal with money, likes ballroom dancing and has a photographic memory. When Mr Bush came to China in November, the two leaders reportedly spoke quite frankly to each other but relations could hardly be described as warm.

In the run-up to Mr Hu's visit, the Chinese released a number of key political prisoners; offered an olive branch to Taiwan, albeit one that Taipei cannot accept; signalled better relations with the Vatican and offered hope that the exiled Tibetan leader, the Dalai Lama, may visit China.

Rise of an eastern superpower

POPULATION

* 1.3 billion

ECONOMICS

* World's fastest growing economy

* Economy has grown 9.5 per cent annually for 25 years

* GDP quadrupled from 1980 to 2000

* 400 million people have been lifted out of poverty in 25 years

TRADE

* 30th largest US trading partner in 1977; now third

* World's second largest recipient of foreign direct investment

* US exports have grown five times faster than to rest of the world. US corporations have invested more than $50bn in China

* Worker earns 5-10 per cent of an American worker's wage

* 2004: Produced half of all digital cameras and 60 per cent of microwaves, photocopiers and DVD players in the world

POLLUTION

* Has 16 of the world's 20 most polluted cities

* Half of the population has polluted water supply

* Produces 3.7 billion tons of sewage a day

* World's largest consumer of coal; second only to US for oil

MILITARY

* 2005: China says it spent $30bn on its military, the Pentagon says $90bn was spent

* 2000: Estimated size is 2.5 million personnel; 10,000 tanks; 400 nuclear warheads

HEALTH

* 2003: UN estimates 840,000 have HIV

* 17 per cent of people live on less than a $1 a day

* One-third of the world's cigarettes are smoked in China

After a carefully choreographed White House meeting -- marred by a demonstrator who shouted at the Chinese leader -- the two presidents pledged to work together to solve the
Iran and North Korean nuclear disputes, but gave little indication how this would be done.

Bush also failed to get a commitment over China's huge 201.6 billion dollar trade surplus with the United States that has become a major domestic concern.

But Hu said in a speech late Thursday that he expected a stronger relationship to develop from the summit and put across the message that China is not a strategic threat to the United States.

"I believe the meeting today was a very productive one and I look forward to a future China-US relationship that is more stable and more mature," he said in a speech.

The United States and China must "respect each other, treat each other as equals and view differences in a proper context and manage them properly," he added.

Concerns have been raised in Washington about China's growing military might and its economic clout in Latin America and Africa, as well as Asia.

But Hu said in the speech that China needs peace to pursue its own economic miracle.

"Let me tell you in explicit terms that China adheres to a path of peaceful development. And it's formally committed to promoting development domestically, and maintaining world peace and promoting common development internationally," he declared.

Hu will on Friday give another speech at Yale University in Connecticut before flying to Saudi Arabia on the second leg of his tour.

At the summit Bush and Hu agreed on the need to ease trade tensions and work together to keep the nuclear ambitions of Iran and North Korea in check.

Bush said the two countries would deepen cooperation "in addressing threats to global security, including the nuclear ambitions of Iran, the genocide in Darfur, Sudan, the violence unleashed by terrorists and extremists and the proliferation of weapons of mass destruction."

Yet the the two produced no concrete sign of progress on a raft of issues separating their countries.

Bush raised the possibility of a tough UN action against Iran over its suspected nuclear arms program. He urged Beijing to use its "considerable influence" over North Korea to rein in Pyongyang's weapons activities.

But after the summit, Hu only stressed the need to "seek a peaceful resolution of the Iranian nuclear issue."

Hu also acknowledged the six-nation talks on North Korea's nuclear arsenal had run into "difficulties" and called on all parties to display flexibility to allow the negotiations to resume.

On Taiwan, which China considers a breakaway province, Bush counseled China to avoid confrontation. Hu responded with a vow to oppose Taiwan's secession from the mainland "by any means."

Bush pressed US complaints about China's currency, market access and rampant piracy -- which critics say fuel the US trade deficit.

Hu acknowledged "frictions" over economic relations but promised only to "continue to advance the reform" of the exchange rate and to extend market opening measures and copyright protection.

Bush delivered another lecture on "the importance of respecting human rights and freedoms" in China but Hu was unapologetic when asked in the Oval Office whether there would be democracy in his country.

"I don't know what you mean by a democracy," he replied. "But what I can tell you is that we always believe in China that if there is no democracy, there will be no modernization."

Stephen Hadley, the US national security adviser, said later that Bush had presented a list of "about six people who are in detention in China that he hoped would be released."

The summit was carefully staged with an elaborate welcome that included a 21-gun salute on the White House lawn, a military band and an American Revolutionary-era fife and drum corps.

But Bush was visibly embarrassed when a protester from the Falungong spiritual movement, which is banned in China, heckled Hu as he spoke.

The woman, a reporter for the Falungong-founded newspaper Epoch Times, nearly drowned Hu out as he made remarks, before she was hauled away by
Secret Service agents.

She was charged with disorderly conduct and an obscure count of "willingly intimidating or disrupting a foreign official," a spokesman said.

Bush later expressed regret, telling Hu, "This is unfortunate, I'm sorry that this happened," according to the White House.

Outside, hundreds of Falungong supporters and pro-Taiwan and Tibet activists shouted for their causes. Pro-Beijing demonstrators hurled back their own slogans.

Analysts said that even if there had been no progress in major issues, the two leaders had at least deepened their understanding of each other.

"He tells me what he thinks, and I tell him what I think, and we do so with respect," Bush said.

For New York Times political analyst David Sanger, Hu's visit renewed an old predicament: "Just about every American president since
Richard Nixon has confronted the fact that his influence over China is far more limited than he once hoped.

"President Bush is now facing that reality midway through his second term, at a moment when the Chinese clearly sense his weakness."

"This was unfortunate and I'm sorry this happened," Bush told Hu, according to Dennis Wilder, a senior official with the National Security Council.

The Secret Service charged Wang with disorderly conduct under local statutes. The U.S. Attorney's office was weighing federal charges of "willing intimidation or disruption of a foreign official," said Secret Service spokesman Eric Zahren.

Outside the White House, hundreds of yellow-clad Falun Gong disciples, Taiwanese nationalists, and Tibetan youth group members demonstrated against Hu and his government.

The protesters denounced China's human rights record, its missile build-up near Taiwan and its 55-year-long rule over the Himalayan Buddhist region of Tibet.

"Communist Party = Tyranny + Lies," read a yellow banner, carried by one female member of Falun Gong, which China outlawed and brutally crushed in 1999.

"Taiwan is not a part of China," read a placard hoisted by one of around 300 Taiwan activists, who reject China's claim of sovereignty over the island. Tibetans, mostly U.S.-based students, called for independence for their homeland.

A U.S. official said Hu's team was probably offended by the incident. "The hardliners on Hu's team are going to ask, why did it take so long for us to pick her up. It is not a good thing," he said, speaking on condition of anonymity.

Zahren of the Secret Service said the woman had passed through "all appropriate levels of security," including a metal detector. She was allowed into the event under a temporary press pass.

Falun Gong, which thrives overseas despite being largely stamped out in China, alleges that government persecution of the group includes a vast system of concentration camps, where doctors harvest inmates' organs for transplants.

China has vehemently denied this, but a U.N. investigator is examining the allegation.

In remarks at Hu's arrival ceremony, Bush did not mention Falun Gong, but he said he would discuss human rights. He urged Hu to allow "the Chinese people the freedom to assemble, to speak freely and to worship."

Hu, making his first official visit to the United States, said he and Bush had "reached a broad and important agreement on China-US relations and regional and international issues of mutual interest."

"We agreed to maintain regular high-level exchanges and increase interactions at various levels," the Chinese leader said after the talks with the US president.

Bush said the two countries would "deepen our cooperation in addressing threats to global security, including the nuclear ambitions of Iran, the genocide in Darfur, Sudan, the violence unleashed by terrorists and extremists and the proliferation of weapons of mass destruction."

Yet the summit, the leaders' first meeting since Bush's trip to Beijing in November, produced no concrete sign of progress on a raft of issues separating their countries.

Bush raised the possibility of a tough UN action against Iran for its suspected nuclear arms program. He urged Beijing to use its "considerable influence" over North Korea to rein in Pyongyang's weapons activities.

But in an implicit rebuff to the US refusal to take the option of military force off the table, Hu stressed the need to "seek a peaceful resolution of the Iranian nuclear issue."

Hu also acknowledged the six-party talks on North Korea's nuclear program had run into "difficulties" and called on all parties to display flexibility to allow the negotiations to resume.

On Taiwan, which China considers a breakaway province, Bush counseled the Chinese to avoid confrontation and unilateral action. Hu responded with a vow to oppose Taiwan's secession from the mainland "by any means."

Bush pressed US complaints about China's undervalued currency, tight market access and rampant piracy -- which critics say contribute to a 201.6 billion dollar US trade deficit.

Hu acknowledged there had been "frictions" over economic relations but offered no new prescription other than a promise to "continue to advance the reform" of the exchange rate.

Bush delivered another lecture on "the importance of respecting human rights and freedoms" in China but Hu was unapologetic when asked in the Oval office whether there would be democracy in his country.

"I don't know what you mean by a democracy," he replied. "But what I can tell you is that we always believe in China that if there is no democracy, there will be no modernization."

The visit came amid mounting concern here over China's growing military and economic clout and increasing influence in regions from Asia to Africa to Latin America.

The summit was carefully staged with an elaborate welcome that included a 21-gun salute on the White House lawn, a military band and an American Revolutionary-era fife and drum corps.

But Bush was left visibly embarrassed when the protester from the Falungong spiritual movement, which is banned in China, standing amid television cameras on the grounds, heckled Hu as he spoke.

The woman, identified as a reporter for the Falun Gong-founded newspaper Epoch Times, nearly drowned Hu out as he made his opening remarks before she was hauled away by uniformed Secret Service agent.

She was charged with disorderly conduct and an obscure count of "willingly intimidating or disrupting a foreign official," a spokesman for the Secret Service said.

Bush later expressed regret, telling Hu, "This is unfortunate, I'm sorry that this happened," according to Dennis Wilder, acting senior director for East Asian affairs at the National Security Council.

Outside the White House fence, hundreds of Falun Gong supporters and pro-Taiwan and Tibet activists shouted for their causes. Pro-Beijing demonstrators hurled back their own slogans.