Iraq is boisterously celebrated a new national holiday — National Sovereignty Day — to mark the withdrawal of most U.S. troops from its cities this week. Though the observance was orchestrated by the government of Nouri al-Maliki for its own political purposes, there was something real to toast. Two and a half years ago, when fresh American forces deployed across Baghdad, Iraq appeared to be spiraling toward sectarian war and possibly splitting into pieces. Today it is as peaceful and prosperous as it has been in decades, and far freer; violence is down 90 percent from its peak and most of the country's political forces are focused on competing in upcoming democratic elections rather than fighting in the streets.