"This is a country that historically has had very little central government. But it's a country with a history of local autonomy and local tribal authority systems."
Some Afghan and international officials have backed direct talks with the Taliban movement, which was forced from power by a US-led invasion in 2001.
On Tuesday, Mullah Omar, the fugitive leader of the group, rejected an offer from Hamid Karzai, the Afghan president, of protection and said foreign troops must leave before negotiations can begin.
McKiernan acknowledged that the 70,000-strong force in Afghanistan could not succeed in tackling the rising Taliban violence without support from local leaders and ordinary people.
"We're not going to run out of bad people in Afghanistan that have bad intentions and we're not going to kill and capture so many of these bad people that it's going to break the will of all the insurgent groups," he said.
However, McKiernan did not go as far as suggesting working with the Taliban leadership to restore order.
He likened his plan to workening with the so-called Awakening movements fighting al-Qaeda in Iraq, but warned against arming tribes to fight against the Taliban.
The general has asked for four additional combat brigades and support forces - about 20,000 troops - to join the fight in Afghanistan and said that international forces could still be successful.
Barack Obama, the US president-elect, has promised to transfer troops from Iraq to Afghnaistan once he takes power in January, but Jaap de Hoop Scheffer, the Nato chief, has urged other nations to support the mission.
"No strategy will work if it is not matched by the right resources," he said on Tuesday.
"All of us, all the Nato allies, need to make greater efforts to the military, economic and civilian development [of Afghanistan]."