This is a key

This is a key quote out of Sen. McCain’s remarks this afternoon at AEI.

Contrary to popular notions that U.S. troops are getting “caught in the cross-fire” between Sunni and Shia fighters, and are therefore ineffective in ceasing the smoldering civil war, the track record is that when U.S. troops stopping [sic] sectarian violence is excellent; where American soldiers have been deployed to areas in turmoil, including Baghdad neighborhoods, the violence has ceased almost immediately.

Similary, the Marines in Anbar province report very positive effects in reducing the non-sectarian Al Qaeda based violence that is the predominant cause of instability there.

Is that true? My recollection is that there was an earlier surge or crackdown in Baghdad. Violence did abate at first but then it rose again. The thinking, if I recall, was that the insurgents just adapted to the new tactics and then the fighting escalated again.

I doubt there’s any real question that in a certain geographical area, with X number of soldiers and sufficiently permissive rules of engagement (two mammoth ‘ifs’) we could stop all the violence. The question is what X number is, whether we have X number of troops available, whether we’re willing to make the area into a free fire zone and whether the whole effort really makes an eventual political settlement more possible.

So what exactly is McCain referring to? And are they examples which have any real bearing on the question at hand?