For Capt. Jim Marckwardt, coming to Iraq in 2005 was like being a kid again. Blackouts, water shortages, car bombs and guerrilla shoot-outs—just like his middle-school years in Peru, where his father worked for the U.S. Agency for International Development in the 1980s. Even the people seemed familiar. He was good at bargaining with Iraqi contractors. "In the U.S., you sit down and negotiate directly," Marckwardt says. "In Iraq you have to build more relationships. It's very similar to the Peruvian way of doing business." He also recognized the sense of honor that drives many Iraqis—another echo of his childhood in Latin America—and has used it to his and his men's advantage.

After moving to Baghdad's traditionally Sunni Adhamiya district last June, Marckwardt barely dodged a grenade on his first patrol. He responded with a cordial letter to the neighborhood. "It's an honor to be in Adhamiya," he wrote. "Adhamiya is known worldwide. The Abu Hanifa mosque [a local landmark] is known worldwide." His soldiers handed out copies on patrol. "I just felt that it was a good way to spread a message," he says. He put his soldiers to work taking barricades off the streets. A few Iraqis immediately joined in.

Greater cultural sensitivity has long been a goal of the U.S. Army in Iraq, but only lately, as soldiers come back for the second or third time and deploy deeper into Baghdad neighborhoods, has it become a reality. It's paid off. Late last summer, Marckwardt bonded with a soft-spoken university professor named Abu Muthana over their shared love of Spanish. Disillusioned with the insurgency, Abu Muthana now commands a U.S.-supported neighborhood patrol group. "We thought the Americans were our enemy," he says. "But we Iraqis woke up and realized we have a common enemy." That's not all they have in common.