Afghanistan has special significance to the world of militant Islam. It was once called Khurasan, along with parts of Iran and Pakistan. Muhammad said: "If you see the black flags coming from Khurasan, join that army, even if you have to crawl over ice, for that is the army of the Imam al-Mahdi and no one can stop that army until it reaches Jerusalem." That is one reason Osama bin Laden chose it as his base, or al-Qaida.
The fundamentalists in the Muslim world are waiting for the prophecy of Muhammad to be fulfilled. Muslims will come and fight because Khurasan (Afghanistan) cannot fall. Whether Shi'a or Sunni, just as certain millennial Christians await the coming of Christ the Muslim world of a certain bent believes it is on the verge of the return of the a precursor of the end times, and that is Imam al-Mahdi.
The Muslims believe the angels of God ("2,000 and 5,000") will come to fight alongside them. The mujahideen read the Qur'an and purify themselves for death before battle. Every time they see the enemy, they see heaven.
I have excerpted some of the relevant portions.
Stay well - stay safe - Stay armed - Yorktown
Which means it can be stopped afterward?
Semper Fi,
TS