IRAQ’S ruling elite has survived Kurdish separatism and Sunni jihadism. But a challenge from its own Shia base could prove the greatest threat. Since July 8th the oil-rich south has been in tumult. In the searing heat, tens of thousands of Iraqis are protesting against the dearth of electricity and water. They have ransacked government buildings, burnt offices of political parties and blocked roads to oilfields and the port. When the caretaker prime minister, Haider al-Abadi, went to Basra to calm tempers with a promise of 10,000 new jobs, demonstrators chased him away. He has since called in the army and militias, imposed curfews and cut off the internet. Over a dozen people have been killed, many of them shot dead.

The government looks on, as if at a passing summer cloud. Come September, say officials, the outrage will subside with the temperatures. Behind the barricades of Baghdad’s vast Green Zone, business continues as usual in air-conditioned palaces. Leaders of Shia factions bicker over the results of May’s disputed election. A manual recount drags on. Party hacks haggle over the most lucrative ministries.

But exasperation in the Red Zone—the rest of Iraq—is near breaking point. Parents cool toddlers in buckets filled with what fetid water drips from the taps. Hundreds of thousands of Iraqis graduate annually with little prospect of a formal job.

At stake is the ethno-sectarian system America installed after its invasion in 2003. For 15 years southern Shias kept it working. They gave the ruling factions their votes, oil wealth and men in a war to suppress Sunnis. But corruption, mismanagement and the costs of four years fighting the jihadists of Islamic State have reduced the southern provinces to Iraq’s poorest. Now they have had enough. Less than half the electorate voted, with turnout lowest in Baghdad and the south. Muqtada al-Sadr, a populist cleric revered in the shantytowns, emerged as the front-runner. “Iraqis have lost faith in the political system,” says Ali Allawi, a former defence minister. “After 15 years it has failed to deliver.”

Few of the totems of the new order have been spared. Protesters marched on bases of the hashd, the militia that increasingly acts as the elite’s praetorian guard. They cried for the expulsion of its backer, Iran, and ripped down the signposts over Basra’s Imam Khomeini highway, named after the late leader of Iran’s Islamic revolution. They even mocked the ayatollahs in the holy city of Najaf. Images of clerical car parks full of luxury cars circulated on social media with the caption “kulkum haramiyya” (you’re all thieves).

Officials blithely assume that the protesters lack staying power. The chief rabble-rouser, Mr Sadr, has been too tempted by power to join the protests. Without him they look disorganised. But that also makes them harder to co-opt. And summer unrest in Iraq has an uncomfortable way of heating up. The revolution against the British in 1920, the overthrow of the monarchy in 1958 and the Baathist coup of 1968 all took place in July.

Some in government circles want a top-down overhaul before Iraq erupts from the bottom. The army remains one of the few institutions popular with Sunnis and Shias alike. But its officer class is probably too depoliticised to revolt. A more likely scenario could be a coup in which a Shia politician declares an emergency and grabs power.

In other times America might have scrambled to prop up Iraq’s democracy. But to the extent that the Trump administration cares at all, it seems interested in a government that keeps the oil flowing and does its bidding against Iran. It is pleased by the anti-Iranian flavour of the protests, but worries that Iranian-backed ministers will help their neighbour bust American sanctions. Ultimately, Iraqis will have to solve their own problems.