The first helicopter landed in the bluish gray gloom before dawn. More than 20 members of an American reconnaissance platoon and Afghan troops accompanying them jogged out through the swirling dust, moving into a forest smelling of sage and pine.
Three more helicopters followed, and soon roughly 100 troops were on the floor of this high-elevation valley in Paktika Province, near the border with Pakistan. They were beginning their portion of a brigade-size operation to disrupt the Haqqani network, the insurgent group that collaborates with the Taliban and Al Qaeda and that has become a primary focus of American counter-terrorism efforts since Osama bin Laden was killed.
The group, based in Pakistan's northwestern frontier, flows fighters into Afghanistan and has orchestrated a long campaign of guerrilla and terrorist attacks against the Afghan government and its American sponsors.
Its close ties to Pakistan's intelligence service, and Pakistan's unwillingness to act against the Haqqani headquarters in Miram Shah, a city not far from the Afghan border, have drawn condemnation from Washington and escalated tensions between two nations that officially have been counter-terrorism partners.
Against this backdrop, the helicopter assault into Charbaran this past week highlighted both the false starts and the latest set of urgent goals guiding the American military involvement in Afghanistan.
The Pentagon plans to have withdrawn most of its forces from the country by 2014. Talk among many officers has shifted sharply from discussions of establishing Afghan democracy or a robust government to a more pragmatic and realistic military ambition: doing what can be done in the little time left.
In the tactical sense, this translates to straightforward tasks for units in the security buffer along the border. While they still have their peak troop presence, American commanders are trying to bloody the strongest of the armed antigovernment groups and to put thousands more Afghan police officers and soldiers into contested areas.
The long-term ambition is that Afghan forces will have the skills and resolve to stand up to the insurgency as the US pull back. And yet, even while looking beyond 2014, American units must fight a day-to-day war.