To land back in Washington after a few days in Iraq is a jarring experience, and not just because of the 30-degree difference in temperature. Conversation here seems to dwell on measuring failure, apportioning blame, and calculating the effect on American politics and American power. In Iraq, the focus tends to be on what is at stake for Iraq and on how to achieve progress there.

By noting this distinction, I don't mean to join with critics of "negative reporting." Iraq-based reporters are focusing on violence because that is overwhelmingly the most important story, shadowing everything else that happens. No one is better placed to evaluate the U.S. occupation than The Post's Rajiv Chandrasekaran, who has lived in Baghdad for its duration, and his definitive and depressing three-part series last week, "Promises Unkept," should be required reading.

What is striking in Iraq, though, is an emphasis on learning from mistakes and moving forward, because there isn't any alternative. This is noteworthy among two groups in particular: Iraqis who have signed on at considerable risk to build a new democratic government, and U.S. soldiers and Marines.

In much of the country, the U.S. military and its allies -- notably but not only Britons and Poles -- provide virtually the only foreign presence, and their resourcefulness and adaptability are impressive. Terrorists have managed to chase away the United Nations, most nonprofit organizations and many for-profit contractors. So the troops not only must fight and kill bad guys but also open vocational schools, manage irrigation projects, rebuild universities, train police and soldiers, mediate ethnic disputes, organize town councils, prepare for elections, and more. All this, while they are stretched thin for their military mission.

Young Army captains spend their evenings in mayors' offices, advising on everything from democracy theory to garbage collection. Slightly older lieutenant colonels organize sheiks' councils. "Every commander in this division has personally run an election," either in Bosnia or Kosovo, says a senior officer in the 1st Infantry Division, now based in Saddam Hussein's hometown of Tikrit. By default, they have become America's nation-builders overseas.

When some Iraqi units fled in the face of attack in April, it prompted a debate here in Washington: Will Iraqis fight for themselves or won't they? In Iraq, allied officers examined cases where Iraqi units had stood their ground (in Mosul, for example), studied why other units had failed and tried to adjust accordingly. Marines near Fallujah discarded numerical quotas for training Iraqi troops and concentrated on finding a few good sergeants. Maj. Gen. Martin Dempsey, commander of the 1st Armored Division, turned to Iraqi party leaders to supply assigned numbers of troops and to tribal leaders for police recruits. He set up new joint operations centers, to enable coordination between U.S. and Iraqi forces even while allowing Iraqis to report up through their own chains of command.

The same kind of improvisational pragmatism is evident in Adnon Palace, where the new Iraqi government is taking shape in a frenzy of corridor encounters and cell phone conversations about armed forces organization, amnesty and reconciliation, paying civil service salaries, and a hundred other gargantuan challenges. "I want to guard against major expectations," said Barham Salih, the new deputy prime minister. "This is a country that is in dire trouble."

For Salih, the reality is that Iraq will be here a year from now, with or without Americans, and the question is how to move it as quickly as possible toward stability and pluralism. He, like every allied general, talks about the need for patience.

But the flip side of the pragmatism is an idealism that also doesn't get much play here -- a clear sense of the stakes. "There are so many powers that don't want us to succeed -- a democracy in the heart of the Middle East," Salih said. "This is changing the course of history."

"This is a revolutionary change," echoed Gen. John Abizaid, who heads the U.S. Central Command, "not just in the history of Iraq but in the history of the Middle East." The moderates fighting for their lives and their country are fighting the same battle against extremism, he said, as is being waged in Pakistan, Jordan and across the region.

"This thing is not going to write itself in six months or seven months," he said, adding: "I think it's probably the most important thing this country has had to do since World War II."