Is the surge working?

I'm really, really sceptical of reports that the surge is working, or the violence is down in Iraq. Obviously, those of us who supported the war have far too much incentive to want this to be true, and to overlook disconfirming evidence.

However, after reading this Michael Yon article, I went looking for some possible disconfirming sources. The Brookings index confirms that US military casualties are down. And the Iraq Body Count seems to indicate that civilian deaths have fallen dramatically; the usual Ramadan surge is entirely absent. (I know that IBC is not an accurate guage of the overall number of deaths, but right now I'm interested only in the direction, and the IBC seems like a good proxy for that.)

Caveats: Ramadan is earlier this year; the usual spike in attacks may not have been a function of the holiday, but of the weather, which steadily cools off throughout September and October. Even if the drop is real and sustained, it may not be attributable to the surge; the 2006 operational tempo may simply have been unsustainable. And if it is working now, that wouldn't erase the 100k+ who have died as a result of the invasion.

But if the falling body count doesn't vindicate past policy, it should guide policy going forward. If Iraq is calming down, to me that probably makes the case for a unilateral immediate withdrawal less compelling.