The disheartening end to America’s longest war raises a number of questions about U.S. national security policy in Central Asia and the future of the newly installed Taliban government in Afghanistan

Perhaps the biggest unknown amid the power vacuum and confusion of the American withdrawal is what the Taliban’s relationship with al Qaeda really is, 20 years after harboring the terrorist group that planned and coordinated the 9/11 terror attack on the World Trade Center and the Pentagon.

The 2020 Doha Agreement, negotiated by Afghan Special Envoy Zalmay Khalilzad under former President Trump, laid the groundwork for the withdrawal of all U.S. forces in exchange for a pledge from the Taliban to prevent any terrorist organization from using Afghan soil to threaten or attack the United States or its allies. 

Taliban fighters take control of Afghan presidential palace after the Afghan President Ashraf Ghani fled the country, in Kabul, Afghanistan, Sunday, Aug. 15, 2021. 

Taliban fighters take control of Afghan presidential palace after the Afghan President Ashraf Ghani fled the country, in Kabul, Afghanistan, Sunday, Aug. 15, 2021. 

WHITE HOUSE ADMITS 'FAIR AMOUNT' OF US EQUIPMENT IN AFGHANISTAN IN TALIBAN HANDS

Taliban spokespersons have made assurances that they would not allow any terror group to stage an attack from Afghan territory, but it remains unclear whether there's an incentive structure in place for the Taliban to prevent al Qaeda or any other group from using Afghan soil as a terrorist training camp.

"It is not clear that the Taliban, which seeks international recognition and legitimacy, is going to want to tolerate or encourage direct attacks on the U.S. from al Qaeda or other extremist groups based in Afghanistan," Kimberly Kagan, founder and president of the Institute for the Study of War, told Fox News.

Smoke rises next to the U.S. Embassy in Kabul, Afghanistan, Sunday, Aug. 15, 2021. Taliban fighters entered the outskirts of the Afghan capital on Sunday, further tightening their grip on the country as panicked workers fled government offices and helicopters landed at the embassy. Wisps of smoke could be seen near the embassy's roof as diplomats urgently destroyed sensitive documents, according to two American military officials. 

Smoke rises next to the U.S. Embassy in Kabul, Afghanistan, Sunday, Aug. 15, 2021. Taliban fighters entered the outskirts of the Afghan capital on Sunday, further tightening their grip on the country as panicked workers fled government offices and helicopters landed at the embassy. Wisps of smoke could be seen near the embassy's roof as diplomats urgently destroyed sensitive documents, according to two American military officials.  (AP Photo/Rahmat Gul)

TALIBAN FIGHTERS BEATING AFGHANS ATTEMPTING TO REACH AIRPORT, VIDEO SHOWS

Kagan, who served in Kabul from 2010 to 2012 working for commanders of the International Security Assistance Force, emphasized that the global jihadist movement will likely continue to emanate from Afghanistan. 

"This does not mean that al Qaeda and other groups will not support the global jihadist cause from Afghanistan," she said. "Even if the Taliban is able or willing to preclude al Qaeda from planning or launching attacks from Afghanistan, Al Qaeda continues to be the leader of the global jihadist movement and will disperse its capabilities from Afghanistan to global affiliates."

Many policymakers and experts question whether the Taliban will ever formally sever its longstanding ties with al Qaeda. According to a United Nations Monitoring report released in June, "the Taliban and al Qaeda remain closely aligned and show no indication of breaking ties." 

The report also cites the Taliban’s ties to al Qaeda have "grown deeper as a consequence of personal bonds of marriage and shared partnership in struggle, now cemented through second generation ties." 

While the UN report notes that al Qaeda maintained minimal and covert contact with the Taliban so they would not stymie the Taliban’s negotiating position with the United States, it also makes clear that Taliban leaders consulted with al Qaeda leaders during the nearly two years of negotiations with the U.S. – and promised them to honor the historical relationship between the Islamist militant groups. 

Al Qaeda pledged fealty to Taliban leader Mullah Omar in the 1990s in exchange for a safe haven in Afghanistan and Mullah Omar refused to hand over Osama Bin Laden to U.S. authorities after 9/11.

Afghanistan

Afghan people climb atop a plane as they wait at the Kabul airport in Kabul on Aug. 16, 2021, after a stunningly swift end to Afghanistan's 20-year war, as thousands of people mobbed the city's airport trying to flee the group's feared hardline brand of Islamist rule.  (WAKIL KOHSAR/AFP via Getty Images)

The 2020 Doha Agreement did not include any enforcement or monitoring mechanisms to hold the Taliban to their loose commitments to prevent future terrorist attacks and trust in the fundamentalist group is virtually nonexistent. It’s also unclear how much the Taliban has reformed or moderated since its previous oppressive and medieval rule of Afghanistan from 1996 to 2001. 

When the Taliban first came to power in 1996 on the heels of a military victory against rival mujahedeen groups, in the post-Soviet civil era war, the Taliban declared Afghanistan an Islamic emirate. Once in power, the Taliban implemented a strict interpretation of Shariah law. Women were forced to wear a burka and banned from school or work, Western style television and music were banned, and public executions were held in a soccer stadium.

WAR IN AFGHANISTAN BY THE NUMBERS

"Whatever the Taliban says in words we can see in their actions that the Taliban has retained the same ideology – violence, brutality, oppression – that was its trademark in the 1990s – and it has not changed," Kagan said. 

Taliban spokespersons have made public statements pledging to respect women and ethnic and religious minority rights, however there is scant evidence that the Taliban have fundamentally altered their rigid extremist interpretation of Islam.

On his address to the nation Monday afternoon, President Biden made the argument that the U.S. had two clear objectives in Afghanistan in 2001: go after those who were responsible for the terrorist attacks and ensure that Afghanistan not be used as a staging ground to launch another attack against the U.S. 

"We did that. We severely degraded al Qaeda in Afghanistan," Biden said. "We never gave up the hunt for Osama bin Laden, and we got him. That was over a decade ago." 

The president went on to say that the mission in Afghanistan all those years ago was never to nation-build or create a unified and centralized democratic state. America’s central goal, to disrupt al Qaeda terrorist training camps and prevent another 9/11-style attack on the U.S., was largely achieved, according to the Biden administration. 

Kagan, along with many others, however, fear that Afghanistan will become what she calls the "second school of jihadism" along with Syria, where al Qaeda affiliates send their fighters to.

Hundreds of people gather near a U.S. Air Force C-17 transport plane at a perimeter at the international airport in Kabul, Afghanistan, on Monday. 

Hundreds of people gather near a U.S. Air Force C-17 transport plane at a perimeter at the international airport in Kabul, Afghanistan, on Monday.  (AP)

KABUL FLIGHTS RESUME AS PENTAGON WARNS OF SWIFT RESPONSE TO ANY ATTACK

Back in Washington, the wider domestic implications of the U.S. exit from Afghanistan and the harrowing and desperate scenes from Kabul’s Hamid Karzai International Airport remain unclear.

"The cold truth is that Americans care much more about keeping safe from terrorism than the humanitarian nightmare unfolding in Afghanistan," Max Abrahms, terrorism expert and professor of political science at Northeastern University, told Fox News.

"This means that Americans can tolerate the Taliban even in Kabul so long as it’s not aiding al Qaeda in committing terrorism outside the region. I do not see the U.S. returning to Afghanistan unless there’s another mass casualty attack on the homeland. I hope the Taliban understands this hierarchy of American foreign policy interests," Abrahms added.

CLICK HERE TO GET THE FOX NEWS APP

At this point, there is no signal for how the Taliban plan to rule Afghanistan. What is clear is that Salafi-jihadist groups around the world, many of which have already made public statements congratulating the Taliban, are reinvigorated by the Taliban’s military victory and will use their success as a template for how to continue their own fights in the global jihadist movement.

"Nothing shows the value of American force presence like the absence of American forces as we’ve seen in the past month," Kagan warned.