The United States is now winning the war that two years ago seemed lost. Limited, sometimes sharp fighting and periodic terrorist bombings in Iraq are likely to continue, possibly for years. But the Iraqi government and the US now are able to shift focus from mainly combat to mainly building the fragile beginnings of peace - a transition that many found almost unthinkable as recently as one year ago. Despite the occasional bursts of violence, Iraq has reached the point where the insurgents, who once controlled whole cities, no longer have the clout to threaten the viability of the central government. That does not mean the war has ended or that US troops have no role in Iraq. It means the combat phase finally is ending, years past the time when President Bush optimistically declared it had. The new phase focuses on training the Iraqi army and police, restraining the flow of illicit weaponry from Iran, supporting closer links between Baghdad and local governments, pushing the integration of former insurgents into legitimate government jobs and assisting in rebuilding the economy. Scattered battles go on, especially against al-Qaida holdouts north of Baghdad. But organized resistance, with the steady drumbeat of bombings, kidnappings, assassinations and ambushes that once rocked the capital daily, has all but ceased.

As recently as the first half of 2007, the idea of an American victory in Iraq seemed like a fantasy to just about everyone, including me. General David Petraeus surged additional troops to Iraq, however, and he transformed the joint American-Iraqi counterinsurgency strategy into what nearly all observers now acknowledge is a remarkable and unexpected success. Few bothers to argue otherwise anymore. What remains ambiguous and contested is the definition of an American victory. It’s slightly tricky for a couple of reasons. Pinpointing the exact date when a counterinsurgency ends - not just in Iraq, but any counterinsurgency - is impossible. There are no final battles. There can’t be. And if we don’t know when the war is over, it can be difficult to figure out what over even means in the first place. So how will we know if we’ve won? Part of the problem here is that the war in Iraq is usually thought of as a single war in Iraq. But there have been at least three wars in Iraq since 2003 - the US-led war against Saddam Hussein’s Baath Party regime, the civil war between Sunni and Shia militias, and the insurgencies against government and international forces waged by a constellation of guerrilla and terrorist groups. All three wars are distinct from each other, and two of the three are already over.