A Pentagon document sent to Congress detailing plans to spend $1.6 billion of additional “training and arming” money on the ISIS war includes a plan to buy AK-47s and rocket-propelled grenades to give to assorted Sunni tribes in Anbar Province.

Joint Chiefs Chairman Gen. Martin Dempsey has talked up arming the tribes for some time, but with many of the tribes not on particularly good terms with the Iraqi central government, the decision was controversial.

The Pentagon is arguing for arming them anyhow, on the grounds that “not arming tribal fighters” will make them reluctant to fight against ISIS, which controls over 80 percent of Anbar.

Only one Sunni tribe in Anbar was on good terms with the central government, Albu Nimr, but ISIS has massacre hundreds of its members since then. Other tribes have so far been more or less willing to accept ISIS rule as at the very least no worse than living under the central government, and it’s not clear who these other tribes even might be.