Pfc. Rob Nunez was gulping Miller Lite from a plastic cup when the subject of President Obama’s plan for withdrawing troops from Afghanistan came up: 10,000 troops were being pulled out this year, said a friend at a roadside bar on the fringes of the Fort Campbell Army base. The rest of the 33,000 “surge” troops would leave in 2012.

Nunez swallowed his beer, let out a stream of profanity before landing on a sentence that he repeats a lot these days. “It’s worthless, and it’s never going to end.”

He had just returned from one of the war’s most terrifying corners to a base that has shouldered much of the U.S. troop surge. In the past 18 months, more than 20,000 Fort Campbell soldiers have cycled through Afghanistan; 131 have been killed.

Nunez, 21, who spent about a year in Konar province near the Pakistani border, cared little that the commander in chief had declared Wednesday night that the “tide of war is receding.” He and his friends, some of the country’s youngest war veterans, have little interest in military policy anymore. Not after Konar.

The last mission is what did it. Nunez’s regiment fought for days in early April to win control of a remote valley called Barawala Kalay. Six U.S. soldiers died, and Nunez still can’t figure out why he wasn’t one of them. Bullets came from nowhere, hitting everything but his flesh.

“It was like fighting ghosts,” he said.

When Obama outlined the beginning of the end of America’s longest war — a phased withdrawal, a handoff to Afghan security forces, negotiations with the Taliban — television screens lit up at the base. In the strip of towns orbiting Fort Campbell, the 100,000-acre base straddling the Kentucky-Tennessee border, reactions came quickly. The withdrawal was too slow, or too fast, or right on the money, depending on the soldier.

Nunez, and many of the men he fought with in Konar, had no interest in joining that debate. When Obama stood in the White House’s East Room, they played video games, watched the College World Series or slept. Nunez, a broad-shouldered, square-jawed soldier from Southern California, went to the gym.

He had joined the Army in 2008, ready to see what war was like after talking to friends who had returned from Iraq. But when he enlisted, resources began shifting. Fort Campbell found itself at the crossroads of two wars, and not much later, Nunez found himself in Konar.

When Obama announced that he was adding 30,000 troops to the effort in Afghanistan — the surge ended up deploying 33,000 — U.S. commanders chose not to send any of them to Konar, a remote and violent area. Instead, commanders focused on pacifying larger population centers in the south.

But as insurgents flourished in valleys near Pakistan, brigades from Fort Campbell’s 101st Airborne Division, which saw its first combat during the invasion of Normandy in World War II, fought some of the Afghanistan war’s bloodiest battles along the hostile eastern spine, in places they never planned to hold.

Days after Nunez’s regiment fought in the battle for Barawala Kalay, U.S. troops emptied out of the valley. The mission was to disrupt a Taliban haven, not to maintain a presence there. Nunez’s tour was up. He flew back to Fort Campbell puzzling over the strategy.

Now, 2 1 / 2 months later, when he hears the word “withdrawal,” Nunez thinks of Barawala Kalay — what he came to see as a painful fight of uncertain value, hastily planned and quietly abandoned.

He and his friends keep their posed photos from a visit by Defense Secretary Robert M. Gates crumpled in glove compartments and stuffed in desk drawers. When al-Qaeda leader Osama bin Laden was killed, their celebration was muted. They were unfazed when Obama came to Fort Campbell in May to congratulate the troops, including the Navy SEALs who killed bin Laden, on a job well done.

“We hear pep talks all the time,” Nunez said. “Doesn’t make the fight any easier.”

More than 10,000 Fort Campbell soldiers, most with the 101st Airborne Division, have returned to the base in recent months, repopulating an entire city with veterans of Afghan provinces and valleys whose names they still can’t pronounce.

Drawing on their personal experience, and often little else, some have come to vastly different conclusions about Obama’s announced withdrawal.

“We could win this thing if we flooded the country. Instead, we’re pulling out. Afghans want to know if we can provide them security. We’re basically telling them that we can’t,” said Staff Sgt. Jimmy Schumacher, 29, who fought in the Wotapur district of Konar.

“The whole time I didn’t know why we were there. And now we’re leaving — after I’ve been shot in the leg,” said Pfc. Stephen Palu, who was also in Konar. He has since recovered from his leg wound.

Seven thousand Fort Campbell soldiers are still in Afghanistan, and more trickle back to base each month, greeted in a decorated airplane hangar and set free to navigate the bars, tattoo parlors and barbershops that pepper the base’s periphery.

Local stores and restaurants, some nearly driven out of business during the surge, are starting to fill up again. Family Readiness Groups of military spouses are waiting for husbands and wives to move back into neat subdivisions. Many know that the pace of withdrawal means that thousands will return to Afghanistan before the combat mission ends in 2014.

When the war is discussed here, it’s often among men who call themselves grunts, who discreetly, or not so discreetly, criticize high-ranking officers and policymakers.

Officers chide these soldiers for talking too much, for letting their narrow experiences inform opinions about the war’s prospects.

“I was the same way when I was an infantry guy in Iraq. You grow out of it,” said Warrant Officer Jeremy Meyer, a medical evacuation pilot, who spent Saturday afternoon playing darts with a group of officers at the American Legion.

Nunez and his friends spend much of their time at O’Connor’s Irish Pub & Grill, where volleyball games and beanbag tosses are punctuated by harrowing stories about a war some have left forever and some expect to see again.

Nunez has two months left in the Army. As it has for many others, the war has shaken his marriage and haunts him in quiet moments.

At O’Connor’s last week, he asked his friends sheepishly, “Are any of you guys having trouble sleeping?” And then later, quietly, “It’s like the images keep playing over in my head.”

This week, men from his company will have their first mandatory meetings with mental health workers.

Through it all, Nunez is trying to adjust to life as an observer of military engagements rather than a participant. He says he’ll try to dismiss big announcements and shifts in policy — messages “from guys who have no idea what it looks like over there.”

But on the night he heard about Obama’s withdrawal, he tried his best to reconcile the Afghanistan of the president’s speech with the hills and valleys he grew to know. He couldn’t do it.

“There’s this gap between what I hear now and what I saw,” he said. “And it feels like it’s growing every day.”

Staff writer Greg Jaffe and staff researcher Magda Jean-Louis in Washington contributed to this report.