Such is true zeal and fortitude.

America is slowly learning that she has never faced an enemy such that exists in the umma of Islam.
For its sin of alignment with Israel at all costs, the nature of the full cost is yet to be accounted. However, one can surmise what it might be - by this:

http://timesofindia.indiatimes.com/world/south-asia/New-Afghan-Taliban-leader-promises-to-continue-insurgency/articleshow/48307760.cms

The previous leader of the Taliban, Mullah Omar hosted Osama bin Laden in Afghanistan. For this the US finally bombed the Taliban out of Afghanistan . . . so it concluded. 
But the Taliban were never formally defeated. They never actually surrendered to the US. 
Their new leader, Mullah Mansoor is of the same cloth as his predecessor, Mullah Omar; and when Mullah Mansoor is ascendant over Afghanistan, he will host Ayman Zawahiri or his successor to continue their war. The was is the REAL WAR between the Islam and America has therefore not ended.