Imagine that it's 2009 and a Democrat is in the White House. He (or she) determines that the U.S. mission in Iraq has failed irretrievably. What happens next?

It is not too much of a stretch to say that Kenneth Pollack and Daniel Byman -- foreign policy analysts who served in the Clinton administration and strong candidates to serve in a future Democratic administration -- have proposed an answer in the form of an "analysis paper."

Pollack and Byman, currently researchers with the Saban Center at the Brookings Institution, do not contend that U.S. defeat in Iraq has become inevitable. It is too soon to know whether the new counter-insurgency strategy being implemented by Gen. David Petraeus will or will not succeed, and they are not among those advocating that his mission be undermined.

But they do believe that whoever sits is in the Oval Office should have a Plan B on the shelf: a course of action that, in the event Iraq collapses, protects American interests as much as possible. "Spillover from an Iraq civil war could be disastrous," they write. "[I]t is imperative that the United States develop a plan for containing an all-out Iraqi civil war... America has too many strategic interests at stake in the Middle East to ignore the consequences" and walk away.

Should the U.S. withdraw from Iraq leaving behind a government not competent to defend itself, Pollack and Byman predict, policy-makers will have to choose between "terrible options and worse ones." Most of the country would quickly be overrun by Sunni groups tied to al-Qaeda and Shia groups tied to Iran. It must be expected that hundreds of thousands of Iraqis will be killed in battles and acts of terrorism. Millions more would flee.

The authors suggest creating refugee camps "along Iraq's borders inside Iraqi territory." Protecting the camps, preventing them from being seized by extremists -- while at the same time keeping the refugees from flooding into such American-allied countries as Jordan and Kuwait -- "would require the extensive and continued use of U.S. forces."

A major "intelligence and reconnaissance effort" would be necessary to identify havens set up by anti-American terrorists groups. Air power and/or Special Forces would need to be deployed to destroy them.

The flow of Iraqi oil almost certainly would be disrupted. Advance planning for the economic impact on the U.S. and the global economy would be imperative. Continued...