Good Max Boot effort setting out the major reasons why the insurgency can’t and won’t win. His points about the lack of a leader and lack of territory are significant, and you would hope that the ex-Baathists and other misguided nationalists in the movement would begin to realize that they are playing a losing hand.
On the other hand, neither factor would prevent the country from slipping into civil war or just plain chaos, which may be the real goal here. The problem, especially with regard to the foreign jihadis, is the extent to which war with America is an end in itself. The problem with fighting nihilists is that you can’t take their nothing away from them. The best we can do on that score is (1) as Boot suggests, do a better job of sealing the Syrian border and (2) keep preparing the Iraqi military to carryu on the fight, since the real endgame for us here is having an Iraqi force willing and able to defend its own territory.
UPDATE: I do think the time will come when we will want and need a fixed exit date from Iraq, once we feel that the Iraqi forces are ready (just as we had fixed dates for the transfer of sovereignty and the Iraqi elections). But setting such a date more than a few months in advance of that day would be a disaster, for reasons Chester explains. And setting an October 2006 date – transparently linked to the 2006 Congressional elections rather than the facts on the ground – would be nothing but politics.