The alliance of common interests was perceived as a rebuff to Isis (the Islamic State in Iraq and the Levant), a jihadist group so hardline it was disowned by al-Qaeda. Isis has been rampaging through the country, pledging to rewrite the region's borders. Yesterday Isis showed on its official Twitter account what it said were pictures of its militants capturing, transporting and executing Iraqi soldiers. Isis said that it had executed 1700.
Ground zero of the current threat is only around 95km to the north of Baghdad. Nouri al-Maliki, the Prime Minister, visited Samarra and said it "will not be the last line of defence, but a gathering point and launch pad".
Security sources said Iraqi forces attacked rebels in al-Mutasim, 22km southeast of Samarra, and drove them into the desert. They also claimed the army had regained control over Ishaqi, a town in the same area, to secure a road to Baghdad. Troops backed by a Shia militia retook Muqdadiya, northeast of Baghdad, and rebels were driven out of Dhuluiya after three hours of fighting with tribesmen, police and residents, according to sources.
Help is clearly on the way. And it could not come soon enough for many.
"I heard the US President speak and his words seemed reasonable," said tribal leader Sheikh Abu Wissam al-Saade at a recruitment centre in the eastern suburb of Karrada, as new volunteers arrived wanting to fight. "I would say one thing, though, he is partly to blame for this mess. He's been refusing to send us fighter jets for the past six years, because [Kurdish leader Massoud] Barzani has warned him not to."
Iraq's immediate future seems sure to be determined by non-state actors and powerful foreign patrons. So much for the state, which has done little more than reel in horror ever since the fall of its three largest cities to a small insurgent force in less than one week.
Those in the provinces revealed that they had already dispatched upwards of 15,000 men - most without training - to Baghdad or beyond. Dhi Qaa Yehya Mohammed Bakr said his province had already sent 2500 fighters to Baghdad, while 25,000 have signed up around the province. Columns of minibuses, some escorted by police trucks, snaked along highways from the south.
As their fightback begins, Baghdad and the south are openly rallying around sectarian symbols rather than a national cause.
Nevertheless, the rapid response to Sistani's call to arms, and the comfort drawn from the prospect of imminent heavyweight firepower, has transformed the jihadist push into a counter insurgency. In one extraordinary week, Iraq has gone from relative safety to mortal danger. It now teeters somewhere in between.
Meanwhile, Rouhani's suggestion that Iran and the US could work together to defeat Isis is a new twist on "my enemy's enemy is my friend", but one that is sure to make life difficult for the insurgent group in the weeks and months ahead.Iraqi tribal leaders and officials are also banking on Isis being unable to maintain the hearts-and-minds approach it has adopted with the Sunni towns and cities, some of which appears to have paid off for them.
"You tell me what you would do if you were me," said Mustafa al-Rai, a mechanic from Mosul who has stayed in the city. "Maliki's people and military were persecuting us. They were treating us like we were rubbish on their soles. Now we have Sunnis coming to town promising to change that. They don't share my beliefs, but they are being reasonable to us."
Iraq's Sunnis have already encountered a previous incarnation of Isis, which from 2004-07 ran roughshod over Anbar province and much of Mosul. With the help of the US army, tribal leaders ousted them, and for several years they remained defeated.
The Syrian civil war changed that, proving to be a lightning rod used to reignite their ambitions. And throughout 2013 the group was again ruthlessly imposing its will over northern and eastern Syria.
This year a local uprising ousted them once more. "What makes you think it will be different this time?" asked al-Rai.
"They will soon reveal their colours. And by then, the new friends [Iran and the US] may have helped us out."
- Observer, AP, Telegraph Group Ltd