The 80,000 and 50,000 figures come from this TWS piece. 80,000 is clearly what he thinks it would take to secure Baghdad all at once: “Conducting Tal Afar-type operations across the entire capital region all at once would require concentrating all available forces in the area and a ‘surge’ of about 80,000 U.S. soldiers.” 50,000 is his ballpark figure for what it would take to do it in phases:
There is every reason to believe that a reformulated operation, proceeding in phases to clear Baghdad neighborhood by neighborhood, but with sufficient force levels to leave significant American troops behind in the cleared areas, would be much more successful. It is impossible to estimate precisely how many more U.S. troops would be needed in the capital area, or in Iraq, without proposing a detailed military plan. But since the high end of estimates for doing the whole area at once produced the requirement for a surge of 80,000 or so, it is very likely that a surge of 50,000 American troops would be sufficient to stabilize the capital.
And 50,000 is not that different from what Kagan and Keane came up with when they sat down and did a more detailed military plan for securing Baghdad in phases (a huge part of the city, Sadr City, was left off the table in their plan). They called for five brigades and two regiments to Baghdad and Anbar, more than 30,000 combat troops (but even more troops than that if you count logistics, etc. to support the combat troops). Bush has proposed sending five brigades and a regiment to Baghdad and Anbar, almost precisely what Kagan/Keane proposed. The difference comes in the way the brigades are being counted. The Bush administration is low-balling them as 3,500 troops each, so it comes up with a lower total number.
None of this is to suggest that all is well with the Bush surge plan or that it exactly mimics Kagan/Keane, but it is unfair to charge Kagan with inconsistency on the numbers.
See, you dummies! (via Sullivan).
I don’t know for sure, but I am of the opinion that the surge, even properly manned, would do little to quell the civil war and would lead to much larger casualty figures for the US. Undermanned and half-assed, and it is almost a certainty.