Andrew Krepinevich's How to win in Iraq does indeed repay careful attention, from beginning to end:
"Rather than focusing on killing insurgents, [coalition forces] should concentrate on providing security and opportunity to the Iraqi people, thereby denying insurgents the popular support they need".
How painful/ironic, then, is the coalition failure to anticipate the vulnerability of pilgrims on the Aima bridge approaching the Kadhimiya mosque.
The event looks unlikely to directly increase support for insurgents. Rather, it could undermine trust in the capability of the nominal central authorities. If this is the case, those who hoped to cause such panic look to have sound tactical sense.
But could the insurgents' actions backfire against them? For one thing, the sense of release among Shias, after suppression during Saddam's time, at being allowed to carry out major ceremonies freely may continue to be the overriding emotion, however great the immediate grief for the minority directly affected by the incident.
One thing that does appear to be the case is that there has not - at least so far - been a sectarian knock-on effect. Rather, nearby Sunni neighbours are reported to have come out in numbers to help in the face of a shared human tragedy.