Fred Kaplan explains why the Afghanistan decision has taken so long:
[C]ontrary to the media's incessant focus on numbers, this has never been a decision primarily about troop levels. Last summer, retired Gen. Colin Powell advised Obama that the key question was not how many troops to send but what those troops should doand that this was primarily his decision, not some general's. Obama seems to be following that advice.
[...]That's what the drawn-out discussions have been about, that's (in part) why it's taken so much time. According to some officials, after each of the eight sessions, Obama has been dissatisfied with the answers at some level and has hammered them to bring back more detail the next timeon the state of the Afghan army, on the impact that various deployments would have on the state of the U.S. Army, on a province-by-province breakdown of Afghan politics and security. All these questions directly, even crucially, affect calculations of acceptable risk or clear futilitythe chances of success or failure.