On this last day of 2014, America's troops in Afghanistan are still a combat force.
On Thursday, their mission changes.
"We will be ending our combat mission in Afghanistan, obviously because of the extraordinary service of the men and women in the American armed forces," President Obama said during a recent visit with Marines and their families in Hawaii.
But there will still be more than 10,000 U.S. troops in Afghanistan.
The American mission begins on New Year's Day with a name change. Operation Enduring Freedom comes to an end. Operation Resolute Support begins.
"Our mission really focuses on train, advise and assist," Gen. John Campbell, the top American officer in Afghanistan, said during a recent interview with NPR. "It's a little bit different. We're not out every patrolling every day with the Afghans."
Not patrolling every day but training Afghans on things like logistics and intelligence collection. Most Americans will be working out of bases.
But American special operations forces — such as Green Berets — will still be on patrol. Working with Afghan forces, they'll track down terrorists. The Pentagon also says that U.S. attack aircraft will come to the rescue of Afghan forces.
"Should members of the Taliban decide to threaten American troops or specifically target and threaten our Afghan partners in a tactical situation, we're going to reserve the right to take action as needed," Pentagon spokesman Rear Adm. John Kirby said.
In other words, the combat mission isn't completely coming to an end next year. And the Afghans will still need help fighting.
"There is no evidence as yet as to how well the Afghan forces are going to be able to do in 2015," defense analyst Anthony Cordesman says. He says Afghan soldiers and police suffered large numbers of casualties this year and are spread thinly around the country. Meanwhile, the Taliban has been chipping away at areas once secured by U.S. forces.
"Now that doesn't mean that the Taliban, the Haqqani network or other insurgents are going to take over or even be able to capture a lot of major cities, but this is an extremely fragile Afghanistan," Cordesman says.
The challenge for Campbell, the U.S. commander, is training his Afghan counterparts and managing the drawdown of U.S. troops. That American force of 10,000 is supposed to drop to 5,000 by the end of 2015.
Those drawdowns tend to be especially perilous, Campbell says. The Taliban can mount attacks to take advantage as American troops withdraw from an area.
"You know you're most vulnerable when you go through transitions, so we can never ever get complacent," Campbell says. "But at the same time we've got a long history here; we've got great partnerships. A lot of what I do at my level is about relationships, about relationships-building."
And a key relationship is with the new Afghan president, Ashraf Ghani. The Americans see the former World Bank official as a far better partner than his predecessor, Hamid Karzai, who ignored rampant corruption and failed to provide basic governance.
Ghani is scheduled to visit the White House early in 2015. The expectation, officials say, is that he will ask for more aid money, and a slower withdrawal of U.S. troops. The American military may also press to keep its 10,000 troops longer to fend off the Taliban threat.
"There is a very palpable sense that security has declined," says Vanda Felbab-Brown, an Afghanistan expert at the Brookings Institution. She says keeping more Americans in Afghanistan for a longer period makes sense.
"That's a very reasonable request," she says. "2015 will be a tough year. That's the year when the Taliban will really test the mettle of the Afghan forces."
But both Ghani and the U.S. military will have to convince Obama, who says America's longest war must come to an end.