Twice in the span of a month, the Taliban has unleashed human waves on one of the U.S. Army's most isolated Afghan outposts. Twice, the American soldiers guarding the tiny fort have beat back the attackers, killing scores of extremists while suffering no losses of their own.

The U.S. troops' skill, and luck, have been remarkable. They're going to need both, as more large-scale attacks seem likely.

The Oct. 7 and Nov. 8 assaults on Combat Outpost Margah, in remote Paktika Province on the border with Pakistan, came almost exactly a year after one of the biggest pitched battles of the decade-long war. An October 2010 attack on COP Margah by hundreds of Taliban foot soldiers wielding rockets and AK-47s resulted in a lopsided tactical victory for the Americans. More than 90 Taliban died in a counter-barrage of gunfire, helicopter-fired missiles and satellite-guided bombs. As in the recent assaults, no Americans died – though the fighting left deep psychological scars.

The sustained fighting around COP Margah underscores the Americans' battlefield prowess and the Taliban's continuing ability to mass large numbers of troops despite concerted NATO efforts to seal off the border with Pakistan and thus strangle the Afghan insurgency. U.S. operations in and around the town of Margah, depicted in my video above, are actually ramping up while NATO activities elsewhere in Afghanistan slowly wind down.

By now the 172nd Infantry Brigade, the unit currently occupying COP Margah's brick walls, chilly concrete buildings and sandbagged bunkers, has a firm handle on the Taliban's tactics. The enemy uses a crisscrossing network of dry river beds called wadis to sneak within firing distance of the football-field-size outpost. "The intent is to mass 150 or more [fighters] in the wadis and then merge from three sides," Maj. Joe Buccino, a public affairs officer, tells Danger Room.

Once the shooting starts, the Taliban know they probably have only a few minutes before the Apache helicopters and Air Force jet fighters arrive overhead and unleash Hell. "When fighters arrive on station, the insurgents can't run away fast enough," said Capt. DeShane Greaser, commander of the Margah troops.

But bad weather on the night of Nov. 8 might have lulled the Taliban into thinking they had the advantage. "They believed the heavy cloud cover and fog would prevent CAS from blowing them up," Greaser said. "It did not."

The Air Force's response was swift and decisive. While the soldiers manned the outpost's walls and bunkers and picked off attackers one by one, F-16s and F-15s raced in from Bagram Air Field. Guided by an Air Force controller named Seth Pena, the jets lobbed eight guided bombs.

The air support arrived just in time, Greaser said. "There was a vehicle-borne Improvised Explosive Device heading to the COP and after the first bombs hit we got reports that the enemy said, 'We're turning around, there are jets overhead."'

No fewer than 70 Taliban died outside COP Margah on Nov. 8. At least, that's the estimate the soldiers came up with after picking up body parts the following day – standard procedure following a major attack.

With a history of bloody assaults stretching back at least a year, COP Margah's American defenders probably realize that it's a question of "when," not "if," another massive attack will target their lonely Afghan outpost.

Video: David Axe