Story highlights Michael Kugelman: Sixteen years since US troops entered Afghanistan, the enduring conflict seems largely forgotten

To eliminate terrorism, we must work to incorporate an economic and diplomatic strategy along with our military strategy, he writes

Michael Kugelman is deputy director and senior associate for South Asia with the Asia Program at the Woodrow Wilson Center. The views expressed here are his own.

(CNN) Sixteen years ago this Saturday, US troops entered Afghanistan.

The decision to dispatch troops was prompt, and the public reaction in America was mostly positive. There was a sense of inevitability: The United States had experienced the deadliest-ever terrorist attack on its soil. It was time to go get the bad guys who planned it and the hosts that offered them sanctuary.

Michael Kugelman

In relatively short order, the deed was done: The US-led mission eliminated the sanctuaries inhabited by al Qaeda and removed its Taliban hosts from power.

And yet, soon thereafter, Americans were reminded of an inconvenient truth: Ending wars is harder than starting them. This was a bitter lesson from Vietnam, and one that would later resurface in Iraq.

Indeed, ever since Washington's immediate objectives were achieved in Afghanistan, it has struggled badly to explain why US troops continue to fight and die in a faraway land. This struggle to articulate a strategy has taken on added urgency as the Taliban insurgency has gained more steam. According to multiple estimates, it now controls more territory than at any time since US forces entered the nation in 2001.