It's the lie that counts
The latest I'm hearing on the cable is that the plan was to disrupt the Ashura commemorations and perhaps assassinate Ayatollah Sistani. Now we hear that the attack was the work of a Messianic cult -- one with "links to Saddam Hussein loyalists and foreign fighters [and] hoping the violence it planned would force the return of the 'hidden imam,' a 9th-century Shiite saint who Shiites believe will come again to bring peace and justice to the world."
'Foreign fighters' in this context usually refers to Sunni extremists, with al Qaida sympathies. Saddam loyalists, if secular, are almost all Sunni as well. So these guys were mounting an attack on Najaf in order to realize the central eschatological hope of the Shia? I'm sorry but that makes no sense. Other reports say alternatively that the attack was Sunni-backed or Shia-backed.
Look, under Bush the U.S. military is trained to lie first and think later. The fact that it makes no sense doesn't matter. It's the lie that counts.