Eleven years ago, murderous men attacked the World Trade Center in New York and the Pentagon in Washington, D.C.  As a result, the United States went to war with the Taliban in Afghanistan, presumably because they harbored al Qaeda, the group that was deemed responsible for these heinous acts.

Eleven years later, even U.S. government officials admit that al Qaeda's presence in Afghanistan is virtually nil. The group's leader, Osama bin Laden, was killed in 2011. Yet, the war in Afghanistan persists.

Now, the U.S. is fighting to quell the Taliban's insurgence. But why? The Taliban no longer harbors al Qaeda.

It's about building a natural gas pipeline from Turkmenistan through Afghanistan and to a port, probably in Pakistan. That pipeline can't be built if the war persists. The Afghan army doesn't have the ability to extinguish the Taliban threat. The Taliban can't overthrow the government and, if they did, it would like look a huge failure for the United States.

So, the war most go on in the minds of U.S. government officials. Countless people die as a result. This will be the lasting legacy of the attacks of September 11, 2001.