Iraq attacks 'aimed at exploiting fragility'
As Iraq suffers its latest wave of bombing and shootings, one of the deadliest, the BBC's Sebastian Usher examines what lies behind insurgents' attempts to spread chaos and discord.
Every month this year, there have been major co-ordinated attacks in Iraq, using car bombs, mortars and gunfire.
Reports on the violence are routinely accompanied by the proviso that it is nowhere near as bad as it once was.
But the rate has accelerated worryingly in June and July - with such attacks now being seen every few days.
The targets have mostly been the Shia community, the security forces and government officials.
The violence is normally blamed on Sunni insurgents.
Fears of a return to the terrible violence seen in 2006 and 2007 were fuelled by a political crisis that emerged almost as soon as the last US soldier had left Iraq”
An umbrella organisation, the Islamic State of Iraq, which incorporates al-Qaeda and other radical groups, has claimed responsibility for many of the attacks.
The motive appears to be to keep Iraq unstable and insecure, undermining the government led by the Shia Prime Minister, Nouri al-Maliki.Sectarian strains
One of Mr Maliki's main commitments has been to try to ensure basic security for Iraqis after years of violence.
That promise has been put increasingly to the test since all US troops finally withdrew at the end of last year.
There were many warnings at the time that Iraqi security forces would be unable to stop a resurgence of violence after the Americans left.
As if to fulfil these prophecies of doom, last January saw several large-scale suicide attacks on mostly Shia targets in Baghdad and elsewhere.
Fears of a return to the terrible violence seen in 2006 and 2007 were fuelled by a political crisis that emerged almost as soon as the last US soldier had left Iraq.
It erupted after Mr Maliki issued an arrest warrant for one of the leading Sunni politicians, Tariq al-Hashemi, on charges of running death squads.
Mr Hashemi fled to Kurdistan and later abroad, as other Sunni politicians denounced the Iraqi prime minister as a dictator.
They accused him of deliberately setting off a political crisis that risked plunging the country back into sectarian conflict between Shia and Sunnis.
The fragile government coalition between Sunnis, secularists and Shia has seemed in danger of total collapse ever since.
Sunni and Kurdish leaders have increasingly come together to oppose Mr Maliki.Regional fears
The crisis has done little to increase Iraqis' confidence in their state institutions, which many dismiss as ineffective and corrupt.
The insurgents appear to be feeding off this insecurity, as well as the sense many Sunnis have that they have been disenfranchised in the Iraq that has painfully emerged in the years after the fall of Saddam Hussein.
What remains unclear is what other forces within Iraq may be backing them and whether they have a more coherent strategy than simply to sow chaos and fear.
The violence and political infighting has raised old questions over whether Iraq can or should remain unified or split into three - Sunni, Shia and Kurdish - either as separate states or autonomous regions.
The conflict in neighbouring Syria has raised new fears as it seems to be turning increasingly into a vicious sectarian confrontation.
Some Shia have expressed fears that if a new Sunni leadership takes power in Syria, it might sponsor more Sunni insurgency in Iraq.
Those concerns will not have been eased by a recent statement by a man claiming to be the leader of the Islamic State of Iraq threatening a new stage in its campaign and appealing for Sunni tribes to join its cause.
The events of the past seven months since the Americans left have given Iraqis little cause for hope that their politicians will be able to work together to face down such a challenge.