As shocking as today's attacks on worshipping Iraqi Shia Muslims are, they were entirely predictable. For weeks the American and British occupation forces had been fearing violence during the festival of Ashura. I know. I was told so several times when I was in Baghdad a month ago.
For the deaths to occur during this festival and in the holy city of Karbala as well as Baghdad is especially significant.
Ashura, which started yesterday, commemorates the martyrdom of Hussain, the grandson of the Prophet Mohammed. Along with most of his family, he was killed by rival claimants to the title of being the Prophet's successor and is buried in Karbala.
The event caused the schism in Islam, which produced Sunnis and Shias. Across the Muslim world, Sunnis make up the vast majority, except for Iran where Shias are predominant, and Iraq, where Shias are two-thirds of the population.
All Shias mourn at Ashura, the more earnest, usually young men, flagellating themselves with whips. Swords and razors are used to selfinflict wounds to bloody effect.
Saddam Hussein did not allow such observance, so this year's festival had added significance. Who is to blame? The chief suspects are probably extremist Sunni Muslims, al Qaeda types, perhaps supported by Wahabi extremists from Saudi Arabia.
Al Qaeda wants more problems for the US in Iraq and Washington is known to be concerned about infiltration from Saudi Arabia and money crossing to support terrorism.
Saudi religious leaders consider a Shia-dominated state on their doorstep to be one of their worse nightmares.
The attacks happened despite all the fears because the Shias insisted on organising their own security rather than involving American troops or other members of the coalition. But with hundreds of thousands of people gathering at Shia shrines, security, except around Shia dignitaries, was effectively nonexistent. Already, though, there is a report that the office of Grand Ayatollah Sistani, the main Shia leader, has blamed the Americans for not providing security.
The bombings will boost the political activism of the Shias who have been unable to secure early elections which would give them political dominance.
Shia militant groups, all backed by Iran to one extent or another, will seek a bigger role.
The spectre of civil war in Iraq, held back while there are signs of political progress, will be awakened. A transitional constitutional document, agreed at the weekend and due to be signed tomorrow, could be an early casualty.
The Shias were seen to have made compromises on their demands over the role of Islam. A cynical alternative explanation could be that Shia extremists, perhaps at Iran's instigation, caused the attack.
With Tehran's support, militant groups have been using fear and intimidation to push their agenda.
To meet the challenge, American and British authorities in Iraq must work with local tribal and religious leaders to defuse the crisis.
It will be a great test. The next few days and weeks will be watched by Iraqis themselves to see whether President Bush and Tony Blair have the mettle to finish the task they committed themselves to a year ago.
Simon Henderson is a London-based associate of the Washington Institute for Near East Policy.
Evening Standard (London)