One word that Gen. Petraeus used to describe the state of Iraq is "fragile." This is bad news:

A suicide bomber blew up a funeral gathering for the nephews of a prominent local American-backed Sunni chieftain in northern Iraq on Thursday, killing 40 people and wounding six others, according to the local police.

The attacker struck inside a tent full of mourners for the funeral of the two nephews of the chieftain, Sheik Ibrahim Arif al-Azawi, who were slain by unidentified attackers this week. Police said the chieftain was a local organizer of the Sunni Awakening Council, a group of largely Sunni militias that with American help have turned against Sunni extremists in Iraq. It was unclear whether he was among the victims of the suicide attack, but another senior chieftain, Sheik Jasim Wihaib al-Azawi, was killed, the police said...read on