BEIJING US President Barack Obama made few breakthroughs but left Beijing on Wednesday hoping he had nurtured a bond with China vital to tackling the gravest global threats.

Any aspirations of a complementary compact with the Chinese people though were muffled by state censorship, on a trip which failed to move Beijing on several key issues such as the value of the yuan, trade imbalances or Iran.

Critics will also argue that China forced Obama to tiptoe around human rights and Tibet, while the spectacle of a communist leader lecturing a US president on capitalism remains a sight to behold.

The massive US debt to China - 800 billion dollars worth - was also reflected in the changed power dynamics of the relationship.

But Obama's aides say he made progress by adding a new layer of complex international issues such as global warming and economic recovery to the familiar agenda of Taiwan, trade and North Korea.

China's growing global reach means Washington and Beijing are building what may be the world's dominant diplomatic relationship.

“In our view, (the trip) has been highly successful in setting out and accomplishing the objectives that we had set for ourselves,” said Jeffrey Bader, Obama's top White House East Asia aide.

“It's an important first step in building a partnership between our two countries to work together on global issues.” At a lavish state dinner on Tuesday, a Chinese military band belted out “We are the World”, the 1980s Michael Jackson charity hit - perhaps offering pointers to the potential of new US-China ties.

Analysts have speculated about a “G2” link-up between China and Washington in which the powers would provide global leadership, but it is unclear whether China is ready for expanded responsibilities.

“My sense is that for the most part, the Chinese do things that are in their immediate interest and not much beyond,” said Elizabeth Economy, of the Council on Foreign Relations.

“They are not at a stage where they want to step up to the plate and assume global leadership.” Victor Cha, who served as former president George W. Bush's top East Asia hand, also warned against inflating expectations of Chinese global action.

“Just because we recognise them as a major global power does not mean they are ready to step up and lead,” said Cha, now with the Centre for Strategic and International Studies.

Despite upbeat White House readouts on Obama's meetings, few key issues on his agenda appear to have been nudged significantly forward during the visit.

President Hu Jintao and Obama on Tuesday pointed to divisions on economics, human rights, international diplomacy, and trade - and their diplo-speak hinted at the crushing formality of their private discussions.

And on Iran, there was no public sign that Hu had shed Chinese reluctance to embrace tougher sanctions over Tehran's nuclear programme.

Washington appears to be trying less to bring China along on Iran, than to ensure it does not obstruct a new sanctions drive at the United Nations.

While taking media hits at home for supposedly showing too much deference to China, Obama's priority seems to be winning long-term trust in Beijing.

“He adopted a conciliatory and respectful tone to speak about divisive issues,” said Liu Qing of the Institute for International Studies in Beijing.

One advantage for Obama unlike the last two US presidents, he took power at a time of stability in US-China relations.

Bill Clinton came to office in 1993 vowing not to coddle “dictators” in Beijing - but over eight years revolutionised the US-China trading relationship.

Bush talked of China as a “competitor” and not a “strategic partner”, and within months was pitched into crisis when a US spy plane was downed in China.

But he left office trusted in Beijing and bequeathed stable ties to Obama.

So will Obama be able to build upon that start?

“There are still several issues that can undermine the relationship,” said Professor Yan Xuetong, executive director of the Institute of International Studies at Tsinghua University.

“(Obama) possibly will receive the Dalai Lama, he will possibly continue to set more sanctions on China's exports to the United States and he still will possibly sell weapons to Taiwan.” US ambassador Jon Huntsman was gushing about the state of relations, but warned China was changing too fast to lay sure bets on the future.—AFP