The terrorist attack on New York's World Trade Center, a landmark of the "U.S. Dollar Empire," on Sept. 11, 2001 astonished the world. The 9/11 attacks marked a turning point in the world landscape. Thereafter, the world landscape has undergone profound changes and entered into a new era of history.

Following the 9/11 attacks, the United States launched the wars in Afghanistan and Iraq under the pretext of combating terrorism. Unexpectedly, the United States has paid severe consequences for the wars, and the wars have led to more terrorism problems than they intended to address, such as frequent suicide terrorist attacks. After many years, there is still no end in sight for the fight against terrorism.

The international financial crisis in 2008 further decimated the U.S. economy. Although the U.S. government has tried all possible means, the economy is still too weak to recover. The two wars and one crisis have made the U.S. economy feeble.

In contrast, emerging countries, including China, Brazil and India, have maintained higher economic growth than advanced countries over the past decade. Emerging and other developing countries have contributed to 47 percent of the world's economic growth during the period. According to the data from the World Bank, the gross economic output of China, Brazil and India ranks second, seventh and ninth, respectively, across the world. The rapid development of emerging countries has promoted the global recovery and advanced the world's multi-polarization process.

Over the decade after the 9/11 attacks, the balance of world power has undergone historical changes. Even the U.S. president had said that the time when the U.S. spared no expense in outside intervention has gone forever. The world pattern has changed from one in which a single superpower dominates the world to one in which the superpower is forced to coexist with multiple great powers, with large nations governing the world. The United States has abandoned the global strategies of "taking preemptive actions" and "unilateralism" and has adopted "multilateralism" and "smart power."

The United States signed and entered the Treaty of Amity and Cooperation in Southeast Asia in 2009 and promised to recognize ASEAN's "leadership" in the region. This indicated the first time that the United States abandoned leadership and voluntarily put itself under the lead of other organizations during the post-war period. Moreover, the United States was again "being led" at the France-led meeting on Libya's post-war reconstruction.

After the outbreak of the Middle East unrest, the United States adopted the policy that there are things must be done and things must not be done and took differential polices towards different countries. It adhered to the principle of avoiding excessive intervention and resisted sending ground forces. For example, the United States allowed their allies to be on the frontline and stayed in the back in the Libyan military action. In terms of Syrian issue, it adopted a strategy of "using the tongue, not fists," and froze the assets of Syrian government and senior officials.

East Asia is a priority for the America's "back to Asia" strategy. Apart from showcasing "muscles" in the region, the United States is more inclined to adopt the so-called "smart power." It sows seeds of discord to stir up trouble, lets other nations make trouble or even backs up both opposition sides at the same time in order to obtain the maximum benefits with the minimum output. However, the trend of peace and development is irreversible, and the United States would find it hard to stir up trouble in the region.

It is sure that the United States has a stronger resilience and correction mechanism. Its leading role in the military, economic and technological areas cannot be challenged for a long time. We should have a sober understanding of this and cannot take it lightly.