Asia's integration process is picking up momentum with the 10-member ASEAN meeting that widens into the 16-nation East Asia Summit, which opened Thursday in Hanoi.

The most intriguing part of the summit is probably the return of the US to Asia and the reaction of China.

US Secretary of State Hillary Clinton, who is on her way to the summit, is scheduled to give a speech on the leadership of the US in the Asia-Pacific region today in Honolulu.

What she is going to talk about was not yet known by the press time, but it is crystal clear she is setting the tone for her Asia trip and what her country is going to sell in Asia.

The US is attending the summit as a special guest, yet it claims to be a leader in the Asia-Pacific region.

Apparently, the US is not a humble guest. And it provokes speculations about the kind of leadership the US is going to play.

The legitimacy of the US leadership in Asia is indeed questionable. Without the involvement of the US, economies in Asia have been doing well in the backdrop of the world financial crisis. And now they are making their way toward regional integration.

With the theme of "ASEAN: from vision to action," the 17th ASEAN Summit and related summits between the bloc and partners focus on ASEAN community-building and cooperation enhancement.

The ASEAN region, which boasts a total population of about 584 million and a combined GDP of $1.5 trillion, has set up a goal to establish an ASEAN Community by 2015.

However, the 10-member group is confronted with a number of problems including a development gap, border disputes and emerging global challenges. And the return of the US is another uncertainty that may further complicate the situation in the region.

The rising of China has been playing a positive role in pushing forward the integration of Asia in recent years. ASEAN and China set up early this year the world's largest Free Trade Area embracing developing countries that covers a population of 1.9 billion people and involves a trade volume of $4.5 trillion.

China has adopted a good neighbor policy, but it is not enough to solve its territory disputes with some Asian countries. China needs more efforts to implement its principle of shelving differences and seeking joint development.

At the same time, some Asian countries and the US are concerned over China's rise and increasing role in the region. Some countries even hope the US will be a counterbalance in Asia to China.

However, the US is not likely to play a dominant role in East Asia as it did during the Cold War era. Bilateral trade between China and many neighboring countries has surpassed that between the US and these countries.

In last November, US President Obama billed himself as "America's first Pacific president" by promising the nations of Asia "a new era of engagement with the world based on mutual interests and mutual respect."

China welcomes a positive role played by the US in Asia's integration but also hopes the US will base its policies on mutual respect.