Fred and Kim Kagan, together with James Dubik, wrote a devastating critique of the Levin plan for simply more training of Afghan troops. First, they reiterate the case against withdrawal:

Withdrawal now would allow Afghanistan to again become a haven for terrorists. It would destabilize Pakistan by giving refuge to terrorist and insurgent groups attacking Islamabad and by strengthening the forces within the Pakistani government and security forces that continue to support the Taliban as a hedging strategy against precisely such an American retreat. Pursuing an offshore strategy of surgical strikes using aircraft and Special Forces units would destabilize Pakistan for the same reasons. Further, if such a strategy could work against al-Qaeda, the commander in Afghanistan, Gen. Stanley McChrystal — the most accomplished practitioner of Special Forces counterterrorism campaigns — would be advocating it. Instead, he is advocating counterinsurgency.

Then, they discuss in detail the question of whether Afghan forces can take on the insurgency without more help from us:

The Taliban maintains significant sanctuaries in Afghanistan that neither coalition nor ANSF forces have been able to contest, especially in the districts around Kandahar City; in parts of Helmand, Ghazni, Uruzgan, Zabol, Paktika and Farah provinces; and in some areas in the north (especially Kunduz province). The districts around Kandahar City are strategically vital because continued Taliban control of those areas threatens Kandahar City — the loss of which could radically destabilize the country. Retaking those districts will be difficult. Raw Afghan recruits or recently formed units without adequate coalition partners are unlikely to be able to do so alone. It is almost impossible to imagine a scenario in which accelerating the expansion of Afghan national forces would create conditions for the elimination of Taliban sanctuaries in strategically critical districts in time to prevent a significant Taliban success.

Read the whole thing.