With US troops about to withdraw from Iraqi towns and cities, there has been an upsurge in bomb attacks - but is this a sign of worse to come, asks Jim Muir, or a last throw of the dice from the militants?
In the baking heat of an Iraqi mid-summer's day, there was a bustle of activity at what is left of Joint Security Station (JSS) Comanche.
It is one of the military bases set up by the Americans, along with Iraqi army forces in the spring of last year, to bring Baghdad and other areas under government control.
JSS Comanche is right on the edge of Sadr City, the huge Shia suburb which we could see stretching away into the heat haze.
Until last year, it was a stronghold of the Mehdi Army militia, the followers of the militant young Shia cleric, Moqtada Sadr, but after a lot of fighting, it was tamed, and the militia melted away.
Now, under the withdrawal agreement, the Americans were busy packing up and moving on. Huge cranes were busy hoisting sections of concrete blast-walls onto flat-bed lorries to be trucked away in swirling clouds of dust.
The troopers from the US 1st Cavalry's Ironhorse Brigade had packed their kitbags and were clambering into armoured vehicles and being driven off.
Two days before the end-of-the-month deadline, this position, now just a wasteland, and its command building, were to be handed back to the Iraqis.
And not to the Iraqi army, whose units had already redeployed elsewhere but to the Ministry of Agriculture, the original owners of the command building, which was their research station.
US troops are supposed to leave Iraqi towns and cities by 30 June 2009
The military base was simply disappearing, swords being turned to ploughshares. Incidentally, I met some Agriculture Ministry officials who had come to inspect their old premises before getting them back.
They were not very happy. Their records and equipment had all gone, years of work lost, they said.
And they were not too optimistic about the outlook either.
As though to underline their anxieties, at sunset, just a few hours after our visit to JSS Comanche, Sadr City was shaken by a massive explosion.
A bomb had gone off in one of its busy street markets, which spring alive at dusk, as the searing daytime temperature starts to drop.
Scores of people were killed, maybe 80 or 90 by the time some of the badly wounded have died.
There was an outburst of spontaneous anger from the survivors. "Why isn't the Iraqi Army protecting us?" they shouted, throwing rocks at the security forces.
This underlined the big fear haunting Iraq, as American forces stand down and the violence appears to escalate dramatically.
Again and again, Shia areas, markets, mosques, busy streets, are being hit by huge bomb attacks, just as happened in the bad old days two or three years ago.
That is why the Shia militias emerged then, their raison d'etre (some would say pretext) was to protect their embattled communities, and to exact revenge - which they did, terribly - abducting, torturing and killing hundreds, indeed thousands, of Sunnis.
Will Shia militias return when US troops leave Iraq?
If, in the coming weeks, the bombs go on, and get worse, and the Iraqi forces are incapable of stopping it, surely the pressures will grow, for the Shia militias to make a comeback.
And then, of course, there would be a real danger of the deadly cycle of sectarian revenge starting up once again.
The Prime Minister, Nouri al-Maliki, went on television to reassure people that the Iraqi forces were capable of keeping them safe. He urged them not to respond to provocations, and to help the security forces by reporting anything suspicious.
The American withdrawal from the cities, he said, was historic, a huge triumph for Iraq.
In fact, the withdrawal that we are talking about is more apparent than real. It is not as though the Americans are suddenly whipping away the tablecloth from under the crockery on 30 June.
They have already greatly scaled down their presence and visibility in most urban areas.
And the troops they are pulling out of positions like JSS Comanche are not going far. They are re-locating to bases just outside the city limits, and they will be ready to step in and help the Iraqi forces whenever asked.
US troops are not yet leaving the country, apart from those brought in earlier for the "surge."
The real test will come later, probably after next January's general elections, when the Americans start disappearing in numbers.
Are the Iraqis forces really ready, and will they stick together, in conditions of sectarian provocation and stress?
Has the government done enough to draw the Sunnis on board, especially the Sunni militias, now known as Awakening Councils or Sons of Iraq, who used to be with the insurgents?
Do people really feel attached to the Iraqi nation, or, are they just waiting for the Americans to go, so they can get on with pursuing the interest of their own sect, clan or tribe?
The truth is, nobody really knows, but a lot more needs to be done in the meantime, if people are to feel confident.
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