As the US withdraws its military from Afghanistan, it is clear that Washington's goal in the country has always been to guarantee American security. President Joe Biden left little doubt to this effect during a speech last week.
"Our single most vital interest in Afghanistan remains what it always was, to prevent a terrorist attack on our country."
Biden's assertion that this interest can be preserved without US military presence is not shared by all US politicians.
Republican member of the US House Foreign Affairs Committee Michael McCaul said last week that Afghanistan was returning to the "terrorist safe haven" it was before the US invasion in 2001.
US Army General Mark Milley has also said he is concerned that militant groups like al-Qaeda and the "Islamic State (IS)" could quickly rebuild their networks in Afghanistan.
Will the Taliban change?
While there is a real risk that these groups can now reorganize in Afghanistan, terrorism expert Daniel Byman wrote recently in Foreign Affairs that Afghanistan is unlikely to again become a base for international Islamist militants, even if the US troop withdrawal makes counterterrorism operations more difficult.
Byman asserts that the Taliban have learned from the past and will behave differently. He added that al-Qaeda has lost a large part of its former strength, and that the Taliban and "Islamic State" are enemies.
South Asian expert Christian Wagner from the German Institute for International and Security Affairs (SWP) in Berlin also considers it unlikely for Islamist militants to reestablish their former strength and presence in a Taliban-ruled Afghanistan.
"They no longer want to be a pariah state and are trying to work towards international recognition," Wagner told DW.
When the Taliban ruled Afghanistan from 1996 to 2001, Wagner points out that the so-called Islamic Emirate Of Afghanistan was only recognized by Pakistan, Saudi Arabia and the United Arab Emirates.
"The Taliban now want to change that," Wagner said. The Taliban also know greater international recognition is only possible if they can adapt their politics, and this especially includes how they deal with international Islamist militant groups, he added.
The world is watching the Taliban
Western countries are not the only ones worried about the Taliban using Afghanistan to harbor international terrorist militias.
To keep tabs on their intentions, Russia has maintained channels of communication with the Taliban for years. China has also increasingly been speaking with Taliban representatives over the past few months. And Iran has also opened dialogue with the Taliban, offering to assist with possible peace talks in the future.
All three of these Afghan neighbors are united in fighting Islamist terrorism, and the Taliban are likely aware of this.
And even after its withdrawal from Afghanistan, the US isn't trusting the Taliban to keep out new terrorist threats.
According to analyst Byman, the US still has well-engineered reconnaissance options available to observe and combat the emergence of Islamist terrorism in Afghanistan should it become necessary.
"The US military has explored ways of using its air bases outside Afghanistan for strikes against al-Qaeda camps, or other methods of operating in the country should it become necessary," Byman writes in Foreign Affairs.
The Taliban, 'IS' and al-Qaeda
Nevertheless, ties between the Taliban and al-Qaeda remain close, according to Edmund Fitton-Brown, head of the UN mission to monitor "IS," al-Qaeda and the Taliban.
"We assume that the leadership of al-Qaeda will continue to be under the protection of the Taliban," Fitton-Brown told US broadcaster NBC in October.
"IS" in Afghanistan, however, has encountered resistance from the Taliban. According to a report published by the UN Security Council in May 2020, "IS" has suffered significant setbacks in Afghanistan, with the Taliban playing a major role.
Militant groups like "IS" and al-Qaeda also have different goals than the Taliban, which is almost entirely focused on expanding its rule in Afghanistan.
The other two groups, however, operate on an international level, and borders do not matter to them.
Analyst Wagner said that these diverging goals affect relations between IS and the Taliban.
According to Wagner, 'IS' accuses the Afghans of concentrating only on their own country and thus valuing it higher than Islam and the goal of spreading Islam.
Al-Qaeda also pursues the goal of spreading Islam, but does so in a different way than "IS," and this does not lead to tension with them Taliban, Wagner said.
"Both groups [Taliban and al-Qaeda] are linked to one another through their common combat experience in Afghanistan, and in some cases, they can hardly be separated from one another," said Wagner.
As the Taliban comes to power in Afghanistan, this could make it difficult for them to define their relationship with al-Qaeda.
Wagner said the dynamic of how relations between the two groups are carried out will likely take place on a local, rather than national, level, and depend heavily on interpersonal relationships.