The problem in Afghanistan is not picking the right or wrong counterinsurgency strategy, but picking any military strategy at all.
McChrystal and Eikenberry's plan for measuring progress is absolutely required if we care at all about the truth in Afghanistan. However, the variable in this plan is not necessarily the ability to produce these assessments, but access to the reliable, accurate information sources which provide the backbone of these assessments.
A US withdrawal does not mean abandoning the Afghans. Afghanistan suffers from too much foreign meddling, not a lack of it. And through all of it, the Afghans themselves remain completely helpless to the fate of their own country.
Answer: Zero. The military shouldn't even be involved in Afghanistan. If we want to achieve our objectives in Afghanistan, we need sustainable, civilian-only solutions.
California's budget crisis is actually much less than they're spending on the war in Afghanistan. $26 billion for the budget vs $38 billion for war. And what do they get for it? It's not better to live in California thanks to the war. It's actually getting much, much worse.