Afghanistan was a necessary campaign to retaliate for the 9/11 attacks planned in Afghanistan by Osama bin Laden and al-Qaeda, operating under Taliban protection. We drove out most of the terrorists until they found a sanctuary in Pakistan's frontier areas. Unfortunately. U.S. leaders made the mistake of embarking on a massive nation-building effort that put us on a war footing. This notion centered on the premise that Afghanistan had to be transformed so that it would no longer be a haven for terrorists.
Afghanistan is in the -middle of an arc of chaos, extending from Central Asia through the Middle East into Africa. We cannot possibly wage Afghan-scale wars in dozens of countries. We cannot even afford to expand the Afghan war into the Pakistani sanctuaries with the type of ground invasion needed to clear out this lawless region.
After 10 years and $500 billion, Afghanistan will likely fall back into civil war as soon as U.S. troops leave. Nation-building in a land of tribes and warlords, with no cultural tradition of central authority, was a fool's errand. The United States needs to leave and change its strategy immediately.