Pulling out is hard to do

The dangerously charming and erudite Jared Greene writes (and I post belatedly):

It's a week's since Purim's end, and I'm still no closer to resolving the persistent question that continues to bug me about the Book of Esther: why can't the king of the Persians revoke his own edict to massacre the Jews? After Esther implores him to save her people, he advises her to write a new decree on royal stationery, authenticated by the royal seal, licensing the Jews to resist the onslaught. Such a strange thing that the sovereign can't supercede or suspend positive law, and in Carl Schmitt's phrase, "decide the exception."

It's not clear whether the ancient Persians had a constitutional monarchy going, or had laws stipulating that the king can't revoke written law, or whether the king honored an ethos of self-restraint. Particularly weird, considering the narrative recounts several volte-faces whereby the king revises his settled opinions about things (like naming Haman his Rumsfeld-like secretary of state, then killing him later)--as if to reinforce the crown's limitations. I hit up a bunch of know-it-all types after the Megillah reading last week, but didn't get any satisfactory answers--probably because I stopped short of bothering the truly erudite with such a silly question.

Does anyone have something for Jared that they might post in the comments? Come on, touch the scepter.