The chaotic and bloody retreat of the US troops from Afghanistan has been widely viewed as the defining moment in Washington's embarrassing failure in its 20-year-old "war on terror."

As Saturday marks the 20th anniversary of the 9/11 attacks, it is time to do some serious soul-searching on why the United States failed in such an inglorious and tragic way.

A number of reasons explain the fiasco, of course, and American double standards in the collective fight against terrorism rank among the top.

For the past two decades, Washington has conducted its counterterrorism campaign with selfish calculations. The world has witnessed that it only attacks terrorists it deems a threat to America's national security, while badmouthing the legitimate measures of other countries to suppress terrorism on their own soil.

To put it bluntly, the United States is trying to monopolize the rights to define who are -- and are not -- the bad guys based on its own foreign policy needs.

The United States under Barack Obama once took Cuba off its terror list when it tried to restore diplomatic ties with the country. Yet after Donald Trump took over the White House, his administration reversed the decision and put Cuba back on the US list of so-called "state sponsors of terrorism."

Such a move by the Trump administration illustrates the irrational decision-making that has defined American discourse on terrorism.

Take the Eastern Turkistan Islamic Movement (ETIM) as another example. The ETIM is on the terror group lists of the United Nations and many other countries.

For many years this radical group with links with al-Qaida has posed serious threats to the security and stability of the world community. However, Washington unilaterally removed the ETIM from its list of terrorist organizations in late 2020.

The United States has also been aiding terrorists for its own self-interests over the years. Since 2004, the National Endowment for Democracy of the United States, largely funded by the US Congress, has provided 8.76 million US dollars to radical forces related to the ETIM, such as the "World Uyghur Congress."

"US double standards on terrorism point to an awkward mindset among American politicians: political violence may be called terrorism only if it is perpetrated by those they do not like," a South China Morning Post commentary once pointed out.

Moreover, Washington has been using anti-terrorism as a political pretext to meddle in the domestic affairs of other countries for its geopolitical interests and global hegemony. Washington's intervention in Syria and its maneuvers to topple the Syrian government are classic examples.

Two decades ago, the United States launched its counterterrorism campaign, claiming to root out global terrorism. Yet its self-serving "war on terror" has brought even more chaos, destruction and death to the world over the past 20 years.

The Costs of War project of Brown University, a leading US research university, has found that the number of people killed directly in the violence of America's post-9/11 wars in Afghanistan, Pakistan, Iraq, Syria, Yemen and elsewhere is estimated at more than 900,000.

And according to data compiled by Save the Children, a London-headquartered international humanitarian organization, nearly 33,000 children have been killed and maimed in Afghanistan amid the 20-year war, or one child every five hours.

The world's sole superpower once tasted the cruelty of cold-blooded terrorists in the 9/11 attacks. Therefore, it ought to rally countries around the globe to beat this common enemy of humanity.

Yet Washington's double standards in the global war on terror have not only damaged America's credibility as a responsible global power, but also eroded the foundations for international anti-terror cooperation.

The world cannot vanquish terrorists if the United States continues to play politics with human lives.

The debacle in Afghanistan has once again laid bare the fact that it is high time Washington abandoned its double standards; otherwise, another 9/11 attack could be around corner.