It becomes a viable state when the insurgency is capable of being squashed by Iraq's own forces, and the democratic processes are entrenched to the point of being unlikely to be reversed.
However, let's address a deeper point by your post. When America fought in Korea, World War II and World War I - people simply did not ask those questions. The point of that war was victory; people did not just think of giving up because a thing was difficult. This latter idea is precisely the implication of what you're saying: because something is long and wearisome and difficult, give up. Such decisions do not lead to successful wars, and furthermore they do not enhance the idea that a country is willing to fight for itself.
Ivan
Sometimes people didn't ask the right questions in WRONG wars either.
I don't think DC Bandita is saying to give up because the war is long and wearisome and difficult, but that the war was wrongly engaged. If we picked the wrong war (and I defintiely think Iraq has drained us and hampered our ability to fight the REAL threat, Iran), the fact that it is long and wearisome and difficult does not detract from its be a colossal mistake.
Let's extend this a bit further. We are still embroiled in Clinton's unauthorized war in Bosnia, what, 10 years later ?
DCBandita, Why do you support Clinton's wag the dog war in Bosnia, but not the effort in Iraq ? Why don't you mind that we've still got troops in Bosnia as well ?
BTW I don't call it a war in Iraq,; rather it is a war on Islamofacism which happens to be targeted on Afghanistan and Iraq at the moment, with defensive actions at home and other places around the world.