Purim Legalities Question #1: Achashverosh complies with Esther's request to undo his decree by issuing a new decree authorizing the Jews to defend themselves. This is peculiar, as one would expect him to simply nullify the old decree. A legislative body has the power to revoke its own legislation. Question #2: How is Achashveroshe's institution of a new tax relevant to the story of the Megillah and therefore worthy of recounting. Question #3: Why did Achashverosh kill the sons of Haman? What did they ever do to him? Question #4: Once Achashverosh was killing off Haman's family, why did he not kill Haman's wife Zeresh? The Big Answer: In the case at hand, Achashverosh could not revoke his own decree because he had a contract with Haman, for which Haman paid consideration of 10,000 pieces of silver. So Achashverosh was not free to simply revoke the decree that he had made. Even a contract can be "breached", though, if one is willing to pay. So why did Achashverosh not revoke his decree and pay back the contract. Achashverosh must not have been able to afford paying off the contract. He was hard up for cash as evinced in his soon instituting a new tax. (He had to pay for that party after all, and Midrashic sources say he owed his kingship in the first place to wealth.) In addition, breach may have resulted in his having to pay damages of "expectation", which would amount to all the wealth people had expected to plunder from the Jews. This would be a fairly large amount which he certainly would not want to pay. However, even if he did not expressly violate the terms of the contract, he seemingly violated its spirit and was therefore perhaps guilty of "constructive breach". This is probably why he killed all of Haman's sons; this way there would be no one to sue on behalf of his estate. He did not kill Haman's wife Zeresh, because women in Ancient Persia did not have property rights and she therefore would not have "standing" to sue on behalf of the estate. But could all the people who expected to plunder the Jews sue for constructive breach? The answer is no - because they were "third party beneficiaries" to the contract and therefore had no "privity" to sue. In addition, just in case they could construct privity to sue, Achashverosh instituted the tax to show then whatever the general populace might try to sue him for in a "class action" he could take right back in a general tax. Res Ipsa Loquitur V'Hamevin Yovin