CAMP TAJI, Iraq — The calendar on the wall reads November 2011.

On the ground is a half-filled can of Copenhagen smokeless tobacco. Scattered here and there are bottles of Gatorade, cans of Rip It energy drinks, poker chips, Monopoly money and razor blades.

Stenciled on a wall is a punchy soldier’s slogan: “I will always place the mission first. I will never accept defeat.” Taped on another is a note of encouragement from a Boy Scout troop back home: “You are our hero and your commitment to freedom is honorable.”

There is even a jar of salsa still in the fridge.

When the American troops left Iraq three years ago, they left behind a fragile country that collapsed into civil war. They also left behind the detritus of soldiers’ lives that, in the ensuing years, was left untouched, frozen in time.

Image A soldier's slogan stenciled on a wall. Credit... Ayman Oghanna for The New York Times

Now that American forces, in much smaller numbers, are returning to help the Iraqis confront the extremists of the Islamic State, they have found themselves reoccupying some of their old places. And they are excavating what feels like a slowly decaying time capsule as they discover the things they left behind.