On Wednesday 11 June, the Al-Qaeda-oriented Sunni Islamist group ISIS seized control of Iraq's second-biggest city, Mosul.
It has taken several other cities in the Sunni-majority north and west. Before 11 June it already had control of Fallujah and much of Ramadi, and of significant areas in Syria.
Nadia Mahmood of the Worker-communist Party of Iraq told Solidarity:
"What's going on now with ISIS is a new phase of the sectarian violence which reached its peak in 2006-7 with the bombings in Samarra".
That simmering sectarian civil war died down in 2007-8 and after. But, said Nadia: "After the Arab Spring [in 2011], the Sunni [minority in Arab Iraq] became more assertive.
"In 2013, [Iraq's Shia-Islamist prime minister] Maliki ended the [peaceful, and not sharply Islamist] protest camps outside the roads to Fallujah and ignored their demands.
"Now in 2014, after the election two months ago, Maliki wants to stay in power and has marginalised even the other Shia parties.
"Because of the sectarian nature of the government, this sort of violence will happen again and again. Socialists need to call for a secular state.
"The left and the labour movement in Iraq are not powerful right now, so first of all we need a secular state without religious identity which will give us ground to build. The target now is to end the sectarian nature of the state".
Some of the roots of this collapse of the Iraqi state lie in what the USA did after invading in 2003. It disbanded much of the Iraqi state machine, including low-ranking people, and promoted "de-Baathification".
At first the USA hoped that pro-US and relatively secular people like Ahmed Chalabi and Iyad Allawi would create a pro-US Iraqi government. But those neo-liberals turned out to be good at schmoozing US officials while in exile, hopeless at winning support from Iraqis in Iraq.
Amid the chaos and rancour which followed the invasion and the destruction of everyday governance, the mosques and the Islamist factions won hegemony.
The US adapted and worked with people like Maliki. As Aso Kamal of the Worker-communist Party of Kurdistan told Solidarity: "The Americans made a political system that depended on balancing three ethnic and sectarian identities.
"Iraq had been a modern society, with sectarian divisions not so deep. These events are the product of the new system America brought to Iraq. Especially with other powers like Turkey and Iran intervening, seeking their allies within the Iraqi system, it has been a disaster". Now Saudi Arabia has seized on the current crisis to call for the fall of Maliki and his replacement by "a government of national consensus".
Nadia Mahmood explained: "I think some of the Ba'thists saw the de-Ba'thification policy as targeting Sunnis more than Ba'thists. In fact there were Shia Ba'thists who held powerful positions in the state, and they were protected because they were Shia.
"So the Sunni Ba'athists went to the Sunni side and the Islamist side, not the Ba'thist side. They held to their religious identity".
According to Aso Kamal, Maliki's government is seen as a Shia government, and that rallies groups like ISIS and ex-Ba'thists against it.
For us in Workers' Liberty, the horrible events confirm the arguments we made during the previous simmering sectarian civil war in Iraq (especially 2006-7) for slogans of support for the Iraqi labour movement and democracy against both the US forces and the sectarian militias, not the negative slogan "troops out". The two-word recipe "troops out" then certainly entailed a sectarian collapse like this one, only worse. Now it is happening, even those who previously most ardently insisted that anti-Americanism must be the first step, and everything else could be be sorted out later, dare not hail the ISIS advance and the Shia counter-mobilisation as "liberation" or "anti-imperialism".
Of course, rejecting the slogan "troops out" did not mean supporting the US, any more than being dismayed at the ISIS advance means endorsing Maliki.
The sudden collapse of the Iraqi army as the relatively small ISIS force advanced shows how corrupt and discredited the state has become.
Nadia Mahmood explained: "Soldiers from Mosul were saying that even when ISIS were still far away from the city, the leaders of the army took off their military clothes and left the soldiers. The Mayor of Mosul told the soldiers to leave. Some of the soldiers are saying that there was a deal".
The knock-on effect of the ISIS victories is a sharpening on the other side of Shia sectarianism. As Nadia Mahmood says: "Now the Shia political parties are becoming closer to each other and calling for resistance. There is a sectarian agenda against the Sunni". Aso Kamal adds: "Sistani and Maliki are also calling for a holy war. This is taking Iraq back centuries. It could become like Somalia. That will destroy the working class. It is a very dark scenario".
Workers' Liberty believes that defence of the labour movement in Iraq, which will be crushed wherever ISIS rules and in grave danger where the Shia Islamists are mobilising, should be a main slogan now, alongside the call for a secular state.
"ISIS", says Aso Kamal, "have announced what they are going to do. Women must stay at home. Nothing must be taught in schools outside the Quran. There will be no freedom of speech. They are like the Taliban".
"I'm not sure how ISIS came to Iraq", says Nadia Mahmood, "and whether they are popular even amongst Sunnis. Maybe they are allied with the Ba'thists. But are there more Sunnis supporting them? Many Sunnis seem very scared and oppose ISIS.
"It is horrible what is going on". But, now they have power and access to big arsenals, "ISIS may keep hold of the Sunni cities, such as Mosul and Tikrit, for some time. It's obviously not the same for Baghdad.
"Bringing in Iranian groups to fight ISIS will only encourage sectarian discourse and maybe accelerate Shia-Sunni polarisation. Already Maliki is accused by ISIS, and by the Ba'thists, of being an Iranian agent. Whether Iranian intervention calms the situation or it worsens it is unclear.
"Many people in Iraq would prefer the United States to attack ISIS. They have come all the way from Mosul to 60km outside Baghdad, killing in their wake. I don't know if they stay longer how many crimes they will commit, how many tragedies are going to happen. People in Baghdad feel very scared now".
That doesn't mean endorsing US bombing. The US’s 12 years of bombing in Afghanistan have not installed a secular state, but rebuilt a base for the once-discredited Taliban.
As Aso Kamal explains: "The Americans have a common front against ISIS now. But the Americans are playing with both sides. They do whatever they think will stabilise the region and the markets, and ignore the future of the people. In reality, they are supporting reactionary forces in Iraq.
"The effect of the developing sectarian war will be to inflame nationalism in Kurdistan. Already the KDP and the PUK [the main parties] are asking people to support them in order to keep the territory which Kurdish forces have conquered".
For the Worker-communist Party of Kurdistan, "the main issue is to keep Kurdistan separate from this war. We say there should be a referendum and independence for [Iraqi] Kurdistan".