【明報專訊】Afghanistan has undergone a dramatic shake-up. The former government forces backed by the US crumbled quickly to the Taliban, enabling it to seize the capital easily without much battling. The Afghan president fled his country hastily, reminding many of the fall of South Vietnam's Saigon decades ago. Two decades ago, the US invaded Afghanistan in the name of fighting terrorism and ousted the Taliban from power in only a few months. But Washington underestimated badly the complexity of the Afghan society's structure. The so-called "democratic government" propped up by immense American resources and military support was like a castle built on sand. It was gradually seen as a burden by Washington and was ultimately abandoned by the Biden administration. The fact that the Taliban swept through the entire country in only a few months is proof of its solid foundation in society. Still, it is also true that the group's past history of practising extremism has raised the doubts and worries of many. Recently, the Taliban leadership has repeatedly sent signals of its willingness to adjust its policy lines. If it can keep the promise and make Afghanistan a "normal country", that will be a good thing for the Afghans, who have long been devastated by conflicts, and for the stability of the surrounding region.