Obama Orders Start to US Troop Withdrawal From Afghanistan

Tonight, however, Gates endorsed the president's strategy, saying it will work.

"Over the past 18 months, our troops have made tremendous progress degrading the capability of the Taliban while enhancing the Afghan security forces. It is critical that we continue to aggressively prosecute that strategy," he said. "I support the president's decision because it provides our commanders with enough resources, time and, perhaps most importantly, flexibility to bring the surge to a successful conclusion."

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On the front lines, many U.S. service members contacted by ABC News said they remain determined towards the same goal.

"We're here to do one thing: We're here to win, and that's what we did, we won," said Sgt. Mendez of the No Slack Battalion, 101st Airborne Division, who did not want to give his first name. "It's going on a decade we've been fighting this war. ... I don't see us getting out of here anytime soon. But we are making a difference, we are taking it to the enemy now."

ABC News' Mike Boettcher contributed to this report.