No moment in the aftermath of the U.S-led invasion has led Iraq closer to civil war than Wednesday's attack that shattered the iconic golden dome of one of Shiite Islam's most revered shrines and set off a wave of sectarian violence.
The massive blast, from explosives planted by uniformed militants who forced their way into the Askariya shrine in Samarra, shattered a thousand-year-old holy place and drove a wedge of hatred between majority Shiites and the Sunnis whose sect held power under Saddam Hussein. For a measure of the magnitude of the event, try this from Iraqi Vice President Adel Abdul Mahdi: "This is as 9/1 1 in the United States."
The Golden Mosque is one of the holiest Shiite sites in Iraq. Its destruction provoked retaliatory attacks against Sunni mosques and imams, and restoring order and imposing restraint will be a major challenge for a government still trying to shape its own leadership structures.
In the next few days Americans will see whether the Iraq they are trying to rebuild, both physically and politically, can hold together. That may take a massive display of leadership by the current government and just as intensive diplomatic efforts by the United States and by Iraq's Kurds, who now are doing as much as anyone to hold together a still-fragile federal government.
There also is a pressing need to find out just who was at the heart of this attack, clearly intended to fracture Iraq, derail the rebuilding and plunge the nation into the chaos of a sectarian civil war. That war now has become the strongest hope for an insurgency that had been eroded by political progress. It's also a hope for al-Qaida in Iraq.
The attack on the ancient Golden Mosque is a crime against humanity that should outrage all Arabs and all Muslims, Shiite or not. It shattered a religious and a cultural site, and it is at once a measure of the desperation, the danger and the depravity of the radicals who are trying to destroy the new Iraq.