The Torah of the redactor obviously met with extremely serious opposition. Here the return to the Land of Israel and the authority of the king, known from the book of Esther, colluded. The king of Persia was impressed by the Torah of G-d, in the hands of Ezra, see Ezra 7. He gave Ezra the worldly power to crush his opposition.
We celebrate on Purim the failed physical destruction of Israel by the hands of the Persian king, the enemy being given into our hands. But the spiritual destruction that the Persian king did accomplish, giving the power of king of Israel into the hands of the Kohanim, is still with us today. V'nahafoch Hu.
