6m000 if one wants to gamble (high risk)
10,000 if one wants to accept the various risks (medium risk)
20,000 if one wants to avoid risk (low risk).
My first reaction is this: strategy means taking the number you want and then posing alternatives by multiplying and dividing by two (is this what they teach as strategy at the War Colleges?). This represents learning from the McChrystal era where his surge proposal was something like 10k vs 40k vs 80k, knowing that the 80k would be tossed out immediately just as 20k is today. The clever folks tinker so that 6,000 is a bit more than half of 10k, so we might not think there is a sophisticated algorithm at work (divide by two).
These numbers are driven by three scenarios:
With 6,000 troops, defense officials said, the American mission would largely be a counterterrorism fight of Special Operations commandos who would hunt down insurgents. There would be limited logistical support and training for Afghan security forces. With 10,000 troops, the United States would expand training of Afghan security forces. With 20,000 troops, the Obama administration would add some conventional Army forces to patrol in limited areas.
The last option is out. Not sure that 4k Americans and a few other folks from elsewhere are sufficient for training ANA, but perhaps provide some logistical support that will desperately be needed.
I get it. This is what the military is supposed to do--provide options. And I have not seen the paperwork behind these numbers, but I could have guessed last month or even last year that these would be the options. We knew 10k was going to be the key number, but to do WHAT? Training or counter-terrorism? Or both? Or support for the Afghan National Army, which cannot operate on its own yet and will probably not reach that capability in a magical two years. Given the green on blue attacks where the people NATO is training are firing on NATO troops, it is not clear how training would be sustainable in 2015.
To do the counter-terrorism mission, more than just special ops and drones are ultimately necessary as that stuff is intel-driven. How does one get intel from around Afghanistan when one is no longer operating around Afghanistan? I have no clue. I guess we will have to wait for more reporting and leaking before we figure out what these numbers really mean, besides lost hours by staff officers who had to come up with slides to fit the x2 and /2 output.