Huge sums have been invested in homeland security, domestic anti-terrorism equipment has been upgraded, and a vast, comprehensive and detailed security system has been established. People who visit the United States are struck by the phalanx of security measures - widespread fingerprinting, digital recognition devices, full-body scans. In airports passengers are often called on to unbuckle their belts or take off their shoes.

Procedures have been upgraded and tightened up, but the context in which the terrorists operate hasn't been fundamentally changed by these measures. Older Al Qaeda operatives may have moved on or disappeared, but new members are active, and keen to hatch another 9/11 event.

In 2011, the US will commemorate the 10th anniversary of 9/11.

Looking back, it is clear that this event has profoundly changed the United States, and also directly or indirectly changed the world. The 9/11 tragedy casts a shadow over many international issues.

When talking about future international trends, we should not forget Osama bin Laden.

If the US experiences another serious terrorist attack like 9/11, what will be the impact on US foreign strategy?

Will US President Barack Obama continue to strengthen the US presence in Asia? Will the value of the US dollar be affected? What would be the impact on the world political and economic situation?

Strategic thinkers need to keep these questions in mind.

The author is a senior editor with the People's Daily. dinggang@globaltimes.com.cn