Last week’s decisive ISIS victory over the Albu Nimr tribe was followed by several days of bloody purges, with hundreds of tribesmen killed. That continued today, with another 36 reported executed.

It’s more than just the defeat of Albu Nimr, a pro-government Sunni tribe, however. Rather, it is yet another dramatic blow to the various Pentagon notions of how their new, expanding war might conceivably be won.

Joint Chiefs chairman General Martin Dempsey had been pushing Iraq to start throwing large amounts of weaponry at Sunni tribal factions in Anbar in an attempt to recreate the Awakening Forces that the US used to some effect against ISIS back during the American occupation.

Albu Nimr was a big backer of the Awakening movement, and also one of the few tribes in it that hadn’t split openly with the Iraqi government in the interim. Yet sectarian distrust meant no weapons were provided to them by the Iraqi government, and they were soundly defeated. The massacres that followed were an example to those who oppose ISIS going forward.

But more than a warning against opposing ISIS openly, the massacres may punctuate the mistrust that already dominates the Sunni tribes’ view toward the central government, and will make other tribal factions, to the extent they still exist, even harder to court to the US side.