Was 13-year mission accomplished in Afghanistan?

U.S. Marines and their British allies ended combat operations in Helmand Province Sunday. But after 13 years of fighting, few believe the original mission was accomplished, reports CBS News correspondent Elizabeth Palmer.

Coalition forces handed over a huge base to the Afghan military and all U.S. Marines have left the most deadly region of Afghanistan.

Defending Southern Afghanistan from the Taliban is up to the Afghans now.

At Camp Leatherneck, a sprawling desert complex, the Marines have been packing for weeks, in preparation to close the chapter on America's longest war.

"I'm sure there's gonna be people asking me did we make a difference in Afghanistan," said Cpl. Matthew Thompson, who has been fighting in Helmand for six months.

"I hope we did," he said. "I know we did. Hopefully it stays that way, for how long I'm not sure."

There have been 2,210 U.S. military deaths on Afghan soil since 2001.

The original aim was to defeat the al Qaeda-linked militants who had planned the 9/11 attacks.

But what seemed a simple objective at the time morphed into a complex battle, not only against violent extremists, but against poverty, drugs and corruption.

"I'm worried that my son has to come back," Thompson said. "The future generation of Marines has to come back and start over again. Much like Iraq."

The drawdown in Afghanistan will continue until the first of January 2015 when a small U.S. force of just under 10,000 military personnel will remain in Afghanistan in a support and training roll.