The killing of cleric Wissam Al Ghrawi in Basra signals a dangerous escalation in tensions in Iraq’s southern province.
It also serves as a wake-up call for the new government in Baghdad which, if it is to win the nation’s trust, must act swiftly to begin unravelling the legacy of years of corruption.
Public protests, such as those triggered by the shameful failure of basic services in Basra, are a barometer of social discontent, to which any government must pay heed.
Al Ghrawi was a leading voice in the protests. Last Friday, he overstepped the mark, apparently calling on demonstrators to take up arms. The following day he was shot dead by unknown assailants in the second attack of its kind on protesters.
Al Ghrawi's call to arms, although doubtless a measure of the extreme frustration and anger in Basra, was undoubtedly irresponsible.
Anyone inciting violence should be subject to the full extent of the law of the land. But it is unconscionable that lives should be forfeited in the battle to secure a fundamental right: access to clean water.
Iraq has paid the price of conflict in recent decades, with too many lives lost for too little.
Al Ghrawi's death is indefensible and, as a result, the powder keg that is Basra is now more explosive than ever.
For months, the greatest challenge facing Iraq’s politicians has been to form a government. With the election by parliament last month of Barham Salih as president and his appointment of fellow unaligned moderate Adel Abdul Mahdi as prime minister, that obstacle has been overcome.
But now the real challenge begins. The government faces multiple hurdles, any one of which, if mishandled, is capable of degenerating into crisis.
Basra’s services must be restored. The federal budget, historically a source of regional discontent, must be balanced to ensure equitable funding for all areas of the country.
The Iran-backed militias, which formed to combat ISIS and are now frustrated by their lack of political power, must not be allowed to sow discord. Iraq's own institutions and security must be strengthened to reduce their dependence on rogue, semi-autonomous forces.
While it is not clear whether the Popular Mobilisation Forces were behind Al Ghrawi's killing, those responsible must be found and brought to justice.
Mr Salih's other challenges include securing badly needed funding to rebuild his country.
He must somehow balance the competing interests of regional powers while protecting Iraq's sovereignty and resisting Iran's interference in his nation's political process.
Writing in The National in January, months before taking up his current role, Mr Salih condemned the corruption and the repeated failure of politicians to stop Iraq's cycle of conflict and terrorism.
Iraq, he predicted, was approaching a defining moment in its history.
That moment, laden with traps for the unwary or the faint of heart, is here. Now, on behalf of all long-suffering Iraqis, Mr Salih must prove he is the man to seize it.