What is its significance? Is it the equivalent of a military order? Or is it more along the lines of an opinion issued by the Pope? Or something else?
“Small” pope, more nearly resembling a patriarch in an Orthodox church. It is a religious call to action. Those who follow Ali al-Sistani as a religious leader (and those who simply respect his “authority” while actually following a different leader) will consider it a moral obligation to carry out his fatwa. Those who do not follow al-Sistani and who do not agree with his position cannot be compelled to carry out the fatwa. There is no coercive act, such as excommunication, to enforce the call–other than the possibility that one’s neighbors may respond harshly if they believe you are deliberately flouting it.
A fatwa in general would be comparable to a papal statement than anything else, so you’re right there, Libertarian.
It depends on whether the Iraqi faithful wish to follow the edict or not:
Looks like he changed his mind:
And the link: CNN