The United States in Iraq, population 16,000, is a country within a country. It has a $6 billion budget, its own airline and three hospitals, and imports virtually all of its food. Its central fortress, otherwise known as the Baghdad embassy compound, is nearly as large as Vatican City.

But what seemed like a good idea seven years ago — when plans to construct the embassy and its various outposts were initiated and U.S. interests in Iraq appeared limitless — now increasingly looks like a white elephant of questionable value and staggering expense, critics say.