Besides, to ensure a strong US presence at the Shanghai 2010 World Expo, Clinton encouraged American companies to participate in the event instead of being deterred by the ban on using federal money for the purpose, and even flew to Shanghai to attend the opening of the US Pavilion. In short, she has spared no effort in promoting US interests and enhancing its image.

But this is where the positive side of the complicated Sino-US ties ends, because they also went through many twists and turns from mid-2009 to the end of 2010. Some of the most important events in this regard are the US' attempt to browbeat China into submission at the 2009 UN climate change conference in Copenhagen, US arms sales to Taiwan and American leaders' meetings with the Dalai Lama, frequent reconnaissance missions by US aircraft and ships in China's coastal waters, the sinking of the Republic of Korea's corvette Cheonan, the exchange of fire between the ROK and the Democratic People's Republic of Korea on Yeonpyeong Island, the presence of a US aircraft carrier in the Yellow Sea, and Washington's support for Tokyo after a Chinese fishing trawler collided with Japan coast guard vessels.

These events prompted the US to change its attitude toward China. Washington announced its "Pivot to Asia" (later characterized as "rebalancing") strategy. Since its influence across the world is on the wane, the US now wants to strengthen its presence in the Asia-Pacific region to contain China's rise by, among other things, preventing the establishment of a regional maritime order that could favor China.

Obama's Asia-Pacific strategy has been redrawn by a group of foreign policy advisers, with Clinton being at its core. In fact, Washington's role in escalating tensions over China's territorial disputes with some countries in the South China Sea and the East China Sea can be attributed to it.

Clinton's attitude toward China has been inconsistent. During her foreign visits, from Africa and South Pacific to South and Southeast Asia, she has repeatedly warned the host nations to be wary of one country, meaning China. And she has lashed out at Beijing's position because of its differences with Washington on the Libyan and Syrian crises.

Despite the tough rhetoric, however, the past four years have seen her wrack her brains to deal with the yuan exchange rate issue, the Sino-Japanese dispute over Diaoyu Islands and the Huangyan Island crisis between China and the Philippines.

The fact is any leader would find it difficult to manage Sino-US ties smoothly. Perhaps the problem lies in what the two countries want: China seeks to safeguard its national interests while the US hopes to maintain the structure that favors its interests.

During Obama's first term as president, relations between the US and other countries also went through ups and downs. In 2009, Obama signed the landmark New Strategic Arms Reduction Talks Treaty with Russia. But later US-Russia relations suffered because of disagreements on Libya and Syria, and Vladimir Putin's re-election as president for the third time.

Therefore, such erratic relationships and Washington's ambivalence over the "Arab Spring" will influence Obama's choice of the next US secretary of state as well as his eastward strategic shift.

The author is the director of the Center for American Studies at Fudan University.

(China Daily 12/15/2012 page5)