ERBIL, Iraq — For the Kurds here in this ancient city, the rewards of war are numerous and obvious. Construction cranes rise from the cityscape. Highway medians are green with shrubbery. A glittering shopping mall with an indoor ice skating rink stands as a totem of American-style consumerism. The only blast walls in sight are those that protect the regional parliament, decorated by sunflowers painted in muted shades of yellow.

Among Iraqis, the Kurds benefited the most from the war, and now may have the most to lose if the political chaos that followed the departure of American forces metastasizes into civil war.

“Are we worried? Yes, we are worried,” said Barham A. Salih, the prime minister of the Kurdish regional government. “Our national interest as Kurds lies in a democratic, federal, peaceful Iraq. We still have a long way to go before we get there.”

The end of the American military role here is an anxious turning point for the Kurds, who were protected by the United States for 20 years, beginning after the Persian Gulf war of 1991, with a humanitarian operation and no-fly zone that halted Saddam Hussein’s killing machine. Now, the consolidation of power by Prime Minister Nuri Kamal al-Maliki evokes painful memories of Kurdish suffering at the hands of a powerful central government in Baghdad. It also places the Kurds in the delicate position of acting as peacemakers between warring Shiite and Sunni Arab factions, a battle in which their own future is at stake.