Spencer Ackerman has done a yeoman's job digging into the details as to whether the 40-44,000 troop estimate by Gen. McChrystal is even realistic to consider, when one counts the number of troops still in Iraq and Gen. Odierno's glacially slow deployment out of that country, the number of troops who have just returned from Iraq or Afghanistan (or Kosovo or the Phillipines or Egypt or any number of other deployments), numbers of troops assigned in Germany and S. Korea, and the number of troops that are left available. It's a pretty close thing.

Obama would have something of a cushion, but not much, in the early months of 2010. An additional five brigades will finish their 12 months of so-called “dwell time” at home between deployments by April 2010, providing an additional 22,600 troops, but by that time, about 10,200 troops will be scheduled to leave Afghanistan, leaving available a net gain of 12,400. More brigades become available in the summer and fall, although others currently in Afghanistan will be ending their scheduled deployments then as well. Under current Pentagon policy, dwell time for the National Guard varies, but can be no shorter than two years, and so it is possible but not certain that two National Guard brigades composed of 6,800 National Guard soldiers might be available for deployment by March 2010 as well, beyond the 24,000 theoretically available now. Pentagon leaders had hoped to extend dwell time this year, but that was before McChrystal’s request for additional troops.

There will undoubtably be a Marine regiment or two included in the mix, but (for all the noise and thunder) the Marines are a small part of the overall "boots on the ground" needed by McChrystal's projection. You can't count on increases from NATO - the Brits may throw another 500 troops into the mix, Germany just announced that its troops would stay another year but didn't commit to increases, and Canada's counting on next year being its last. I sincerely doubt that the other countries are going to do anything different. And I am sure not going to count onany sudden near-term increase of professionalism or competency in the Afgan army.

So my question is this: Did McChrystal select, and the Joint Chiefs endorse, a 40-44,000 troop increase in Afghanistan because it was the right number, or because it was in fact the upper limit of available active duty troops (assuming that the White House will not ask Congress to authorize the call up of more Reserves and National Guard units)? The authorized increase in troops that Congress allowed a few years ago isn't going to kick in enough replacements to really count in any significant way. As I and others have noted, increasing the US troop strength to 102,000 or so still is going to be insufficient to be successful in securing Afghanistan in any time less than several years. If this is the upper limit, that there will be no other active troops available in brigade-size units, then we're really limiting our strategic options to "influence" anyone else in the world.

This is probably a good indication of why the White House is really trying to understand what the options are and what the implications are. As Mark Grimsley notes, there is a general consensus that there is no need for a quick decision in a military sense, given that the situation is stable - AQ is contained, the Taliban aren't about to take Kabul, and our troops aren't on the edge of re-directing the Taliban's growth any time soon.

The real division of opinion is about whether completion of the strategic review is time urgent in a political sense. Does the length of the review reflect deliberation or vacillation, strength or weakness? Where people come down on this essentially reflects their opinion of Obama.

Which is why the Republicans are already set to take cheap shots at the White House no matter what the decision is, and despite any rationale for the final direction that President Obama identifies. I can understand Obama's focus on the economy and on health care - these domestic issues capture the attention of the public and he needs the political capital from the presidential election that is running out. But now we're finally in that point in time where Obama will have to announce his final decision. There's a lot riding on this decision, and I hope that Obama has the sense to identify his exit strategy and timeframe as justification for that decision.