It appears that the official storyline that the Shiites, while being attacked in several terrorist incidents, have not struck back, is not entirely accurate.
I earlier suggested (in regard to the consequences of the constitution pasing or failing):
Of course, Sunni Arabs who feel cheated would probably attack in a more conspicuous way than would the Shiites and Kurds, as the latter could use the government and police forces to carry out revenge, whereas the Sunni Arabs would be limited to the much less covert insurgency.
While the specific instance I was referring to (the constitution failing) did not come to pass, the general idea that Shiites would take out their anger through more "official" channels than the Sunnis (who do it through insurgency) seems to have come to pass (the verdict on the Kurds is still out).
I also commented on an earlier story on revenge killings here a little less than two months ago.
That is all.