In Western Iraq, A Bloody American Legacy

Dan Zak: AL ASAD AIR BASE, Iraq — The dust storm swallowed the horizon and then the soldiers, who leaned into the windy blur to load rucksacks onto vehicles pointed homeward. At 3:30 a.m. the next day, their Army battalion would roll out under the cover of darkness, concluding their mission to advise and train Iraqi security forces in Anbar province.

The swath of western Iraq the battalion was leaving behind has seen the bloodiest points of the war, but also some of the most promising. Since the war began, 1,332 U.S. soldiers have died in Anbar, nearly one in three of all American fatalities; but none have been killed in action in the province in more than two years.

In 2006 alone, there were …