The Biden administration's chaotic withdrawal from Afghanistan and the Taliban's failure to fill the security vacuum caused by the collapse of the US-supported Afghan army have raised questions about the competence of both.
Neither predicted the sudden Taliban takeover, nor did they make preparations for its aftermath.
As it pulled out its remaining troops, the White House mounted an emergency airlift to evacuate thousands of US citizens and hundreds of thousands of Afghans at risk of Taliban abuse. The administration's poor performance could undermine confidence in the US among regional rulers and world leaders who have relied on Washington to take the lead in international affairs.
Taliban leaders, including movement co-founder Mullah Abdul Ghani Baradar, returned from exile in Pakistan and Qatar four days after their fighters swept into Kabul last Sunday week unopposed. However, al-Jazeera reports they are still discussing an inclusive caretaker government that would include notables from all ethnicities and tribal backgrounds.
Meanwhile, no overall authority has been put in charge of daily affairs; administrative offices and banks have not reopened and Kabul's airport remains closed to normal traffic. The World Health Organisation has been unable to bring in emergency supplies for 300,000 people displaced during the past two months.
There is no central command and control over thousands of guerrilla fighters who belong to a variety of disparate rival factions. Consequently, Taliban gunmen who have no training in crowd control have proven unable to guarantee security throughout the country or even mount an effective security operation around the airport, where scores were killed in a suicide-bomb attack by the Isis-Korasan, or Isis-K, terror group on Thursday.
Fearful Afghans can be expected to try to flee the country overland once air evacuation routes close at the end of this month.
On the domestic front, the attack is likely to force the Taliban and the US to co-operate in the longer term in the intelligence and security sphere as well as in the immediate term during the evacuation process, and while the US attempts to wreak revenge on Isis-K.
Collaboration between these two enemies is likely to encourage Isis-K to step up attacks on the Taliban and foreigners remaining in Afghanistan. This would be bad news for humanitarian organisations providing the poorest Afghans with food and health care.
Isis-K is a small extremist faction that sees itself as the Taliban's strategic rival, and accuses it of apostasy and "nationalism" by focusing on Afghanistan, thereby refusing to join the wider jihadi campaign to impose the rule of Islamic State, Isis-K's parent movement, in Central Asia.
What do the experts say?
Terrorism experts Amira Jadoon and Andrew Mines, writing on conversation.com suggest Isis-K could pose a threat to Afghan minorities, civilian institutions, de-miners and foreign humanitarian workers.
UN operations and other international aid organisations could face violent disruption although they provide 18.5 million needy Afghans with food and heath care.
Emboldened Isis branches across the region and further afield are likely to step up attacks in Syria, Iraq, Yemen, Egypt's Northern Sinai and north and sub-Saharan Africa. Other jihadi groups could be encouraged to join forces with Isis, their members could defect to Isis, and disaffected youngsters could swell its ranks.
Al-Qaeda affiliates aligned with the Taliban could be weakened while more radical jihadis could shift to Isis-K in Afghanistan if they come under pressure in countries where they are based.
Middle Eastern rulers are uncertain allies in the battle against extremism as they have fielded jihadi proxies in conflicts in Afghanistan, Syria, and elsewhere. They have distanced themselves from the latest Taliban takeover of Afghanistan but could switch to support if the US collaborates with the movement.