Major Op in Helmand Valley underway in Afghanistan

"We're doing this very differently," Nicholson said to his senior officers a few hours before the mission began. "We're going to be with the people. We're not going to drive to work. We're going to walk to work."

Similar approaches have been tried in the eastern part of the country, but none has had the scope of the mission in Helmand, a vast province that is largely an arid moonscape save for a band of fertile land that lines the Helmand River. Poppies grown in that territory produce half the world's supply of opium and provide the Taliban with a valuable source of income.

The operation launched early Thursday represents a shift in strategy after years of thwarted U.S.-led efforts to destroy Taliban sanctuaries in Afghanistan and extend the authority of the Afghan government into the nation's southern and eastern regions. More than seven years after the fall of the Taliban government, the radical Islamist militia remains a potent force across broad swaths of the country. The Obama administration has made turning the war around a top priority, and the Helmand operation, if it succeeds, is seen as a potentially critical first step.