By Jonathan Marcus
BBC News, Washington
In a city that is increasingly tuned to bad news from Iraq, a report from the Brookings Institution, one of Washington's leading foreign policy think-tanks, makes sombre reading.
Many are sceptical more US troops will help pacify Iraq
"With each passing day," it says, "Iraq sinks deeper into the abyss of civil war."
It argues that the Bush Administration's policy has to change "to reflect the painful reality that the US effort to bring peace and stability to Iraq has failed."
Unlike last year's report from the bi-partisan Iraq Study Group, whose goal appears in large part to have been consensus at home, this Brookings study is a tightly-argued case for urgent practical steps to deal with a looming catastrophe.
Its title - Things Fall Apart: Containing the Spillover From An Iraqi Civil War - says it all.
Things in Iraq are bad now, but they could indeed still get much worse.
Implicit in the report is an assumption, as Kenneth Pollack - one of its co-authors - put it, that President George W Bush's plan to send over 20,000 additional troops to Iraq is probably the last chance to stabilise the country.
Military experts here in Washington are not writing off the chances of the so-called "surge", but they are far from optimistic either.
Professor Eliot Cohen of the School for Advanced International Studies at Johns Hopkins University told me that the new Bush strategy was less about troop numbers and more about the man selected to command them.
The emphasis is on preventing the Iraqi conflict from spreading
He referred back to remarks attributed to a British officer - Field Marshall Montgomery - when Britain was struggling with the Malaya insurgency in the 1950s.
"First we need a man and then we need a plan," he said, and this according to Prof Cohen is very much the approach being taken now in Iraq.
The new US commander there, he told me, Gen David Petraeus "is quite unusual among all American generals".
"He has been thinking hard about this. He has a terrific background on the ground and he has a fabulous network of contacts. He's been told he can have anyone he wants to work with him. That's really the most important thing that's been happening."
Much though, he argues, also depends upon the Iraqi government itself - is it willing or able to act in a less sectarian fashion?
This, according to Prof Cohen "has to be one of the great unknowns".
"Clearly," he says, "they haven't behaved very well up to this point".
And even if they do seize the moment, his fear remains that this all may be too late.
This, then, is where the Brookings study kicks in.
It argues that the key goal for the Bush administration now should be to prevent the crisis in Iraq from spilling over into neighbouring states.
This spill-over could take various forms - floods of refugees, outright military intervention, damaging economic effects, terrorism or even new insurgencies in other countries.
What is needed, according to Kenneth Pollack, is a new policy of containment to insulate Iraq's neighbours from the corrosive effects of a full-scale civil war.
For make no mistake, while there are many calls here in Washington - from Democrats and dissident Republicans alike - for some kind of phased US withdrawal, the simple fact is that the worse things get, the less the Bush administration will be able to walk away from Iraq.
Can the Iraqi army battle militants without substantial US help?
The regional stakes are just too high.
The Brookings plan would involve a mixture of measures.
Stepped up financial assistance to Iraq's neighbours would go hand-in-hand with the pull-back of US troops from Iraqi population centres to the country's borders.
Here they could prevent foreign intervention from both regular or irregular forces and set up safe-havens where refugees could be protected and cared for.
Where the Brookings report shares common ground with the Iraq Study Group is in its stress on wider diplomatic efforts.
The Brookings study calls for US engagement with Iran, but argues that this should be through a contact group involving all of Iraq's neighbours.
In effect, the Brookings authors believe that engagement with Tehran should only be at a level proportional to Iran's ability to actually help solve Iraq's problems.
The Brookings study also says that there should be a renewed diplomatic effort to solve regional problems like the crisis in Lebanon and the Israel-Palestinian dispute.
This study is not saying that the President's new strategy of troop reinforcements will fail, but that it clearly could, and that America must then be prepared to deal with the consequences.
Abandoning Iraq is not an option.
And if containment is to work, the report says there must be a resolute commitment by both the US and the whole international community.
A study of previous civil wars, it argues, suggests that half-measures and incremental steps only make matters worse.