MARJAH, Afghanistan - With bandoliers of bullets wrapped over both shoulders, U.S. Marine Lance Cpl. Seth Little knelt in a trench, his machine gun pointing toward a clutch of farmers in a field who stared back.

The 23-year-old from Bremen, Ga., scanned the horizon for Taliban gunmen who were maneuvering unseen somewhere across this rural battlefield, ordering civilians out of their homes in apparent preparation for a fight.

Eight months after U.S.-led forces launched the biggest operation of the war to clear insurgents from the southern poppy-growing district of Marjah, it wasn't supposed to be this way.

Today, the world's most powerful military is still struggling to rout guerrillas who stage complex hit-and-run attacks there every day.

The conflict in Marjah lingers even as another massive American-led clearing operation is under way 100 miles to the east, in neighboring Kandahar province. NATO commanders there are touting recent successes in seizing ground from Taliban militants who, as in Marjah, once roamed freely.

NATO and embedded journalists say many Taliban fighters there have fled or gone underground in the face of withering air power. Gun battles have markedly declined - in some places they have ended altogether - and the biggest threat is hidden, homemade bombs.

Farmers have returned to plant once-abandoned fields, and new allied outposts are being set up to hold ground.

The gains in Kandahar, though, come at a time when Afghanistan's fighting season is winding down with the arrival of cold weather, which thins out the vegetation insurgents rely on for cover to stage attacks.

Winter is traditionally the time when Taliban militants disappear into the mountains to rest and regroup before resuming the fight in the spring. The challenge for coalition forces will be to maintain their gains.

Previous operations hailed as successes in the same area in 2006 and 2007 saw Taliban fighters re-infiltrate in the months that followed - mainly because there were not enough coalition troops to stop them. American commanders argue that this time, there will be.

The daily fighting in Marjah, however, offers a grimmer image of what the security landscape in Kandahar could look like in the summer, when President Obama has said he hopes to start a drawdown of U.S. forces.

With the 30,000-man surge bringing the American troop total to 100,000 in Afghanistan, Obama is hoping to quickly reverse the tide of the increasingly unpopular war, which entered its 10th year this month.

But extra troops do not automatically equate to success.

The February assault on the poppy-growing hub in Helmand province was supposed to be the first stage here of the counterinsurgency strategy called "clear, hold, build."

But Capt. Chuck Anklam, who commands 2/9's Echo Company in a northern swath of Marjah, said all three stages are now going on simultaneously - and none of them is complete.

"Due to the nature of the insurgent activity and the way that the enemy fights - disguising themselves as farmers during the day and having weapons caches hidden throughout . . . we don't truly clear the area, we hold the area," said the 34-year-old from Fort Lauderdale, Fla.

He has tried to maximize the American presence in Marjah by spreading forces out as much as possible, basing them at 13 small outposts occupied by only a squad or two of Marines each, and a similar number of Afghan soldiers.

Marines in Marjah are spread thin not only on bases, but on patrol, when they typically split squads up into two or three even smaller teams.

The strategy, they say, has proven effective, allowing troops to cover more ground and reduce the number of attacks, almost all of which are initiated by Taliban fighters.

The insurgency in Marjah is crude, but effective: Militants use wires or kite string to set off homemade bombs fashioned mostly from ammonium nitrate, commonly used here as fertilizer.