Late in 1963, shortly before he was assassinated, U.S. President John F. Kennedy asked Canadian Prime Minister Lester B. Pearson for his opinion on how the U.S. should cope with escalating unrest in Vietnam.
Peason: “Get out.”
JFK: “That’s a stupid answer. Everyone knows that. The question is how do we get out?”
How, indeed? As JFK had finally come to understand, military conflicts, justified or not, are like a Chinese finger trap: it’s easy for a political leader to order the troops in, but very tricky to pull them back out (just ask the British about Northern Ireland, the Russians about Chechnya, or even Pearson’s Canadian successors about southern Afghanistan).
Good luck to President Clinton, President McCain, or President Obama (alphabetical order) in January 2009 — they’re all smart and well-intentioned people, but they’re going to find that the trap has already been pulled very tight, and there’s not much room left to wiggle free.
Quoderat 
It probably starts with asking “What would happen if we just up and left?” and then working your way from there.
It’s not about intelligence and intentions so much as being disciplined about fully understanding the situation, countermeasures and trade-offs. Status quo is always easier and yet has no guarantee of being better.
Obama has the right strategy. What you do is you tell Iraqi politicians that if they want to keep their power and prerogatives after June 2009 (16 months after Jan 09), they will have to start taking responsibility (political, economic, military, security) for their country now.
You tell them that the freebies (particularly bodyguards from Blackwater) and blank check from american tax payers will stop in June 2009.